Mom's family is in Shanghai, so I've been there a couple times, and went there this here, less than two weeks ago. Right now, its all about the Expo in Shanghai. I would recommend not going, and standing in line for it(Saudi Arabia-10+hours, Germany 4+, Japan 5+, and so on.), and the tickets are relativley expensive, about $40 USD. If you have time, and are bored, with money in your pocket burning to spend, go either early in the morning, run to a big one(Germany and Japan are popular), or go in the evening where the lines move super fast. If the latter, buy a night ticket, not a normal ticket.
If you're Chinese or can look the part, and can speak the Shanghai dialect(sp?) go to some of the Shanghai parks. Not big, but there's lot of stuff to do there. If you have time, go to the Science and Tech muesuem. You can probably skip the IMAX movies there. Has a lot of stuff. Also recommending heading out to Suzhou to vist the Ming gardens, espically the Humble Admistration's one. Wouldn't want to get a guide, as you can just find a large tour group and follow. No one really cares. Also want to view the Bund. Amazing view, and if you can get on a boat, even better.
As for food, don't go to the overpriced tourist stuff. In the morning, try and find a good place that sells long fried things that are french fries on steriods IMO called you tai(pingyin wrong, but whatever), as well as da bin, a sort of pancake thing. Can get an amazing breakfast at a price of about $5 RMB, less than $1 USD, and its pretty much the same thing as the "geninue" Shanghai stuff they give you at tourist places. Lunch/Dinner going to the tourists restaurants is alright, unless you speak Shanghai dialect. Then, go to any restaurant in the area around where you're staying. I would recommend asking the hotel for this, or an uncle that lives in Shanghai
.
Lot of stuff to see IMO. Post pics, or it didn't happen.