Ooh that area is great. Eating: Hymens is the best if you want seafood. Oysters and shrimp are in season and at their cheaepst. Now Hymen's is very busy all the time but well worth the wait, it is also in the historic district. I suggest going to lunch there, the wait was like 10-15 minutes (very short for that place). Market Street and King street are for shopping and in the historic district. King is more antiques and unique shops, Market is historic shops, crafts, local artists, and you can get the famous sweetgrass baskets. They have carriage tours by day and ghost tours by night.
Downtown has a tourist office, very cute and easy to find if you get a map. Most touristy shops have downtown charleston maps. The Aquarium is very impressive I think, and does not take long. From the Aquarium you can go to a few historic museums or chatch the ferry to Ft. Sumter. The first shots of the Civil War were fired there. It is a great boat ride because you get a view of Rainbow Row and the coastal communities. I saw lots of dolphins.
Get a map and drive around the island communities, it is wonderful. The Ashley-Cooper bridge takes you from downtown to the best island. It is the HUGE double bridge, breathtaking. You can rent bikes on that island and go look at the huge mansions built.
Charleston has great theatre, and the College of Charleston is probably having productions right now. They do wonderful shows (my alma mater) and the tickets are under 15$.
Other restaurants: TBonz on Market, Sticky Fingers near Market, I do not remember the name but its famous so ask anyone, it is a local place downtown named after a dog and is known for having the previous owners who died a number of years ago come back for visits.
Whew that is a lot, well let me know if you need anymore information.
My friends arrive tomorrow night at my house then we will head out early Saturday morning. I can't wait! I am SO ready to have a fun weekend with my friends. 
