Philly always has big bashes for 4th of July. If you go to gophila.com, there's info. Evidently, this year's concert (on the steps of the Art Museum) is headlined by Elton John. I think they've got fireworks over the Art Museum and over the river, too. Not sure... it's been 6 years since we lived there.
They do have a big celebration and all I can think of right now is I remember it's sponsored by Sunoco, at least in past years it has been. It all sounds like a lot of fun to me, just never made it to any of it. I think there is also stuff on the Delaware waterfront that goes on.
It's all called the Welcome AMerica celebration. Remembered today.
Philadelphia is hosting a revisit of the Live AID concerts on July 2, 2005 as an aniversary party to bring global awareness of the "world 8" or something global leader conferences to be held later this summer. The concerts are free but you must get tickets. I'm sure you can pick them up on line. Also to inform you that if you are planning on staying at a hotel/motel etc. you had better book it now! I always go to the mountains for 4th weekend (wouldn't miss it!) but LIVE 8 sounds like a lot of fun!