It's really worth catching; I go multiple times every year. They practice right next to the stadium and there are bleachers there. After practice certain team members, usually by position, come over to the fence and sign autographs. The Pro Shop is open, and they sell food (but not cheaply). The stadium has never been open to the public when I've been there, but you can get a little taste of what it's like inside by looking through the gates on the lower level. If you have kids, they have the NFL Experience going (inflatable games, etc.) and sometimes the Punt, Pass & Kick tryouts as well. It's a good time; I hope you get a chance to see it. Calling first is a good idea as sometimes practice times change.