The best place to find the line-ups is the TranceAddict forums, they set up a special WMC forum on there, almost all the nights get announced there first, so thats the best way to find the good line-ups and tickets. And always get tickets early, as prices go up and a lot of events sell out.
As for accom, if you've got some cash I would suggest staying in one of the big hotels, Shelbourne/National/Gansevoort, as these all have nightclubs and pool parties that you get in for free if you stay there, and all the big names play. If not, there are tonnes of hotels all along South Beach, best get in now though, as prices go up as soon as everything is officially announced.
PS tip for the best party in WMC, go to Crosstown Rebels present Get Lost at the Electric Pickle. It starts at 6am and runs all day, awesome music, crazy people and a proper party atmosphere. In a bit of a rough area, but totally worth the trip.