the folks at maplight.org look at what lobbyists get for what contributions in Congress:

On March 14 of this year the House passed an amendment that rejected retroactive immunity for phone carriers who helped the National Security Agency carry out the illegal wiretapping program without proper warrants. Ninety-four House Democrats voted in favor of this measure–rejecting immunity–on March 14, then ‘changed’ to vote in favor of the June 20 House bill–approving immunity. 

“Why did these ninety-four House members have a change of heart?” asked Daniel Newman, executive director of MAPLight.org, “Their constituents deserve answers.”

MAPLight.org’s research department compiled PAC campaign contributions from Verizon, AT&T, and Sprint and correlated them with the voting records of all House members who voted on last week’s FISA bill. (The analysis used data from CRP; contributions were from January 2005 through March 2008). Here are the findings:

Comparing Democrats’ Votes (March 14th and June 20th votes):

Verizon, AT&T, and Sprint gave PAC contributions averaging:

$8,359 to each Democrat who changed their position to support immunity for Telcos (94 Dems)
$4,987 to each Democrat who remained opposed to immunity for Telcos (116 Dems)

88 percent of the Dems who changed to supporting immunity (83 Dems of the 94) received PAC contributions from Verizon, AT&T, or Sprint during the last three years (Jan. 2005-Mar. 2008). See below for list of these 94 Dems.

All House Members (June 20th vote:)
Verizon, AT&T, and Sprint gave PAC contributions averaging:

$9,659 to each member of the House voting “YES” (105-Dem, 188-Rep)
$4,810 to each member of the House voting “NO” (128-Dem, 1-Rep)

http://www.cnewmark.com/2008/06/are-the-telecom.html