http://www.rsc-ne-scotland.org.uk/mashe/2010/11/twitter-list/

// Add list of twitter usernames to a Twitter list
// coded by @mhawksey
// Available under Creative Commons Attribution-ShareAlike 2.5 UK: Scotland License
var SCREEN_NAME = "";
function onOpen() {
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var menuEntries = [ {name: "Add to a List", functionName: "addToList"},
                      {name: "Purge a List", functionName: "purgeList"},
                      {name: "Tweet", functionName: "tweet"},
                      {name: "Configure", functionName: "configure"} ];
  ss.addMenu("Twitter", menuEntries);
}
function getScreenName() {
  var oauthConfig = UrlFetchApp.addOAuthService("twitter");
  oauthConfig.setAccessTokenUrl(
      "https://api.twitter.com/oauth/access_token");
  oauthConfig.setRequestTokenUrl(
      "https://api.twitter.com/oauth/request_token");
  oauthConfig.setAuthorizationUrl(
      "https://api.twitter.com/oauth/authorize");
  oauthConfig.setConsumerKey(getConsumerKey());
  oauthConfig.setConsumerSecret(getConsumerSecret());
  var requestData = {
    "method": "GET",
    "oAuthServiceName": "twitter",
    "oAuthUseToken": "always"
  };
  var result = UrlFetchApp.fetch(
      "http://api.twitter.com/1/account/verify_credentials.json",
      requestData);
  var o  = Utilities.jsonParse(result.getContentText());
  SCREEN_NAME = o.screen_name;
}
function twitterList(method, list, query){
  if (SCREEN_NAME==""){
    getScreenName();
  }
  var requestData = {
        "method": method,
        "oAuthServiceName": "twitter",
        "oAuthUseToken": "always"
      };
   try {
      var result = UrlFetchApp.fetch(
          "http://api.twitter.com/1/"+SCREEN_NAME+"/"+list+"/members.json"+query,
          requestData);
      var o  = Utilities.jsonParse(result.getContentText());
    } catch (e) {
      Logger.log(e);
    }
   return o;
}
function purgeList(){
  var list_id=Browser.inputBox("Enter list name to purge:");
  while(twitterList("GET", list_id,"").users.length>0){
    var object = twitterList("GET", list_id,"");
    for (var i = 0; i < object.users.length; ++i) {
      twitterList("POST", list_id, "?_method=DELETE&id="+object.users[i].screen_name);
      Logger.log(object.users[i].screen_name);
    }
  }
  Browser.msgBox("List purged");
}
function addToList(){
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var dataSheet = ss.getSheetByName("To add to Twitter List");
  var dataRange = dataSheet.getRange(2, 1, dataSheet.getMaxRows(), 1);
  //get list name to add users to (must already exist)
  var list_id=Browser.inputBox("Enter list name to add users to:");
  objects = getRowsData(dataSheet,dataRange);
  for (var i = 0; i < objects.length; ++i) {
    var rowData = objects[i];
    if (rowData.fromuser!="" ){
      try {
        var o = twitterList("POST", list_id, "?id="+rowData.fromuser);
        dataSheet.getRange(i+2,2).setValue("Added");
      } catch (e) {
        Logger.log(e);
      }
    }
  }
  Browser.msgBox("The list now has :"+o.member_count+" members");
}
//////////////////////////////////////////////////////////////////////////////////////////
//
// The code below is reused from the 'Reading Spreadsheet data using JavaScript Objects'
// tutorial.
//
//////////////////////////////////////////////////////////////////////////////////////////
// getRowsData iterates row by row in the input range and returns an array of objects.
// Each object contains all the data for a given row, indexed by its normalized column name.
// Arguments:
//   - sheet: the sheet object that contains the data to be processed
//   - range: the exact range of cells where the data is stored
//   - columnHeadersRowIndex: specifies the row number where the column names are stored.
//       This argument is optional and it defaults to the row immediately above range;
// Returns an Array of objects.
function getRowsData(sheet, range, columnHeadersRowIndex) {
  columnHeadersRowIndex = columnHeadersRowIndex || range.getRowIndex() - 1;
  var numColumns = range.getEndColumn() - range.getColumn() + 1;
  var headersRange = sheet.getRange(columnHeadersRowIndex, range.getColumn(), 1, numColumns);
  var headers = headersRange.getValues()[0];
  return getObjects(range.getValues(), normalizeHeaders(headers));
}
// For every row of data in data, generates an object that contains the data. Names of
// object fields are defined in keys.
// Arguments:
//   - data: JavaScript 2d array
//   - keys: Array of Strings that define the property names for the objects to create
function getObjects(data, keys) {
  var objects = [];
  for (var i = 0; i < data.length; ++i) {
    var object = {};
    var hasData = false;
    for (var j = 0; j < data[i].length; ++j) {
      var cellData = data[i][j];
      if (isCellEmpty(cellData)) {
        continue;
      }
      object[keys[j]] = cellData;
      hasData = true;
    }
    if (hasData) {
      objects.push(object);
    }
  }
  return objects;
}
// Returns an Array of normalized Strings.
// Arguments:
//   - headers: Array of Strings to normalize
function normalizeHeaders(headers) {
  var keys = [];
  for (var i = 0; i < headers.length; ++i) {
    var key = normalizeHeader(headers[i]);
    if (key.length > 0) {
      keys.push(key);
    }
  }
  return keys;
}
// Normalizes a string, by removing all alphanumeric characters and using mixed case
// to separate words. The output will always start with a lower case letter.
// This function is designed to produce JavaScript object property names.
// Arguments:
//   - header: string to normalize
// Examples:
//   "First Name" -> "firstName"
//   "Market Cap (millions) -> "marketCapMillions
//   "1 number at the beginning is ignored" -> "numberAtTheBeginningIsIgnored"
function normalizeHeader(header) {
  var key = "";
  var upperCase = false;
  for (var i = 0; i < header.length; ++i) {
    var letter = header[i];
    if (letter == " " && key.length > 0) {
      upperCase = true;
      continue;
    }
    if (!isAlnum(letter)) {
      continue;
    }
    if (key.length == 0 && isDigit(letter)) {
      continue; // first character must be a letter
    }
    if (upperCase) {
      upperCase = false;
      key += letter.toUpperCase();
    } else {
      key += letter.toLowerCase();
    }
  }
  return key;
}
// Returns true if the cell where cellData was read from is empty.
// Arguments:
//   - cellData: string
function isCellEmpty(cellData) {
  return typeof(cellData) == "string" && cellData == "";
}
// Returns true if the character char is alphabetical, false otherwise.
function isAlnum(char) {
  return char >= 'A' && char <= 'Z' ||
    char >= 'a' && char <= 'z' ||
    isDigit(char);
}
// Returns true if the character char is a digit, false otherwise.
function isDigit(char) {
  return char >= '0' && char <= '9';
}
​