If you want some serious Senior Bowl information, look here and here.
This year's game has been touted as the most talent-rich in years. When you scan the rosters, you'll know why. The guys slated to be drafted in the top ten skip this game, since there is not much they can gain. Guys rated 11 and after will show up. Almost every healthy senior projected as a mid-to-late first rounder will participate.
Bill Parcells skipped the Senior bowl in '03 and '04 but attended last year. I can't say it was the reason he drafted better, but going to Mobile didn't hurt. He'll be back in Alabama this week.