I've been a member at Mod The Sims for many years because their custom content for TS2 was so amazing, and continues to be great with TS3, though not as prolific due to some of the difficulties of the new way the game works compared to the previous versions. The people there are also very helpful. The mods available range from fixing actual problems with game play to things that are just fun additions to the game, and each mod shows how many people have downloaded it, as well as a comment section attached where you can ask questions specific to that mod (or any other content), and the creator can respond directly (if they're still active, and if they're not there's a warning on the main page of the content showing that they haven't responded in x amount of time). You can still download the stuff if the creator isn't active, but if you have problems they won't be around to help you, though many of the other members are willing and able to try.
I find Awesome Mod to be very useful, but like others have already said, their forum is a place you want to avoid if at all possible. If you find you do need help there, my advice is to READ READ READ everything you possibly can find about your problem before you actually ask a question. That's pretty good advice for any forum, but while here and at MTS the moderators will kindly tell you "this has already been asked" and point you in the right direction, over at the "awesome" boards, you'll be lucky if anyone takes the time to actually show you where the question has already been answered in between the insults.