As those of you who live here or have visited know, Philadelphia is a great city with a rich history, and plenty of things to do.
The Philadelphia Travel Planner is a great place to get started, as it has links to all the information you'll ever need to get to Philly, and what to do when you get here. The Philadelphia Tourism Network also has some neat stuff, including a breakdown of things to do in categories such as "Galleries, Museums," "Food, Shopping, Restaurants," and "History, Culture, Science." (History buffs will not want to miss the Liberty Bell and Independence Hall.)
For those of you with fast modems, check out Liberty Net, which has a bunch of clips, movies, and other multimedia you can download on Philly.
If you'd like a more personal recommendation of something to do in Philadelphia, why not send an Email to Amy or John?