Try the Aggressive and Street skating forum of Inline Planet. Read what's there and google terms that seem relevant, or that you don't know. Post your questions.
Most important, find, local to you, where skaters are doing what you want to do. Talk with the skaters there about what kind of skates to get, and where to get them. If you don't know where to find skaters, ask at a sporting goods store that sells skates. (Some stores will know, some will not, so that'll tell you how much that store knows about skating.) A good cop will tell you if there's anyplace that skating is OK.
When buying skates, most important is that they fit well.