Below we have a list of all the polls used on this site. Only nonpartisan polls are used; polls taken by pollsters paid for by one of the parties are intentionally omitted. The dates given are when the poll started and ended. The polls for each state are sorted in descending order of their midpoints. Incumbents are denoted by an asterisk.
The data are also available as plain text and in .csv format for use with Excel. In the latter, the first column is the day number of the midpoint (Jan. 1, 2012 = day 1.0) and the second is the poll length in days.
The site also has a page describing the Senate races, including brief descriptions of the situation, the names and photos of the candidates, and links to their campaign pages, Wikipedia entries, and state parties.