If you go to the preview section here and find ESPN NFL Football the links to the videos from football fridays are all at the bottom. Pretty much all sites have these.
Some beta footage was taken and is spread around the web. THere are some videos of that at
www.nfl2kx.com along with the football fridays vids.
Some videos that aren't part of football friday can be found at
www.gamerchuck.com.
lbzrule has been giving his impression of the game at
www.football-gaming.com and has some videos over there.
If you have Gamerspot Complete or wouldn't mind getting it you can find more videos there.
There's a nice overall video of upcoming ESPN titles including some nice football footage at
www.espnvideogames.com