Any decent restaurants that cater to southern cooking, like fried green tomatoes, southern fried chicken, candied yams and such?
I know that Heirloom leans in that direction with some offerings but I know of no other.
Check out Rex 1516 on South Street, it is not really soul food or a super traditional menu but is definitely southern.
In the northwest part of the city check out Geechee Girl Cafe and Chef Ken's Kitchen, I haven't been to either but have heard good things; Anthony Bourdain recently visited the latter.
Ms. Tootsie's does Southern/soul food (link below). I don't see fried green tomatoes on their menu, but they definitely have Southern fried chicken, candied yams, etc. I haven't actually been there, but it was recommended by a friend who is originally from the South.
I tried it a couple times, food was ok but very expensive for what I found to be average. It is a very trendy club-like atmosphere, actually it is a club after 10pm or so and has two floors with bars above. A nice place with very attractive staff but more for going out than for getting down with some homestyle food. Cocktails were extremely sweet however.
ETA: I just checked out the menu online, looks like the food prices have been toned down from what I remember.
The multiple locations of honey's sit and eat would cater to this kind of cooking. Now its not entirely "southern" more comfort food from around the world but they have country gravy, country fried steak, honey fried chicken fingers with scallion hush puppies and fried green tomatoes on their menu year round.
Khyber Pass does mostly Louisiana-style food but they have several Southern classics on the menu - hushpuppies, fried okra, greens, fried catfish, fried green tomatoes and biscuits. It's more bar than restaurant but it's not crazy early in the evening.
In Doylestown, MOMs -- Maxwell's on Main -- has a New Orleans/southern-influenced menu. Fried pickles, fried green tomatoes, crawfish cakes, gumbo, very good fried chicken when we were there. Southern sides like collards (which were also a very nice version), creamed kale. I think they have bands or djs upstairs some nights, so if that bugs you, go a little earlier.