I like this site; shows a bunch of the polls in comparison.
http://www.pollingreport.com/wh2004.htmBUSH vs. KERRY: Among likely voters; with leaners, where available. (See registered voters.)
Survey BUSH KERRY Margin Includes Running- End Date % % Bush Kerry mates?
Zogby 8/14 Bush 43 Kerry 50
Gallup 8/11 Bush 50 Kerry 47
ICR 8/8 Bush 48 Kerry 48
Time 8/5 Bush 44 Kerry 51
Democracy Corps (D) 8/5 Bush 45 Kerry 52
FOX/Opinion Dynamics 8/4 Bush 43 Kerry 48
ABC/Washington Post 8/1 Bush 48 Kerry 49
CNN/USA Today/Gallup 8/1 Bush 51 Kerry 47
The only one that counts is in November though.