The internet is bringing increased transparancy to the workings of the US Congress as C-SPAN is now publishing an index of its House and Senate floor proceedings -- The C-SPAN Congressional Chronicle. According to the site, "the video recordings are matched with the text of the Congressional Record as soon as the Record is available. It only includes members who appeared on the floor to deliver or insert their remarks. The text included is what the member submitted. Each appearance has a video link where users can watch and listen to the actual statements."
The site states that available coverage includes the 108th (2003-2004), 109th (2005-2006), and 110th (2007-present) Congresses. It seems that the 107th (2001-2002) and 106th (1999-2000) Congresses were added in late 2007. Apparently, C-SPAN is in the early stages of populating their content as not all the video is available online yet. Earlier Congresses are expected to be added as the video is digitized and indexed at the rate of two Congresses per year.
Source: beSpacific, dated February 26, 2008