what to install on server to develop internet mobile application?

I'm creating a recommender system which most of calculations are going to be processed on the server side. I've installed Netbeans 开发者_C百科and emulator, and tried the "Hello World" program. Every offline thing's fine. To develop a recommender system, it is necessary to work online (i.e.,send and receive data from server). However, I have no clue about the technology used. What to install on the server? Or what I should set up next? thanks

Use HttpConnection or use soap for calling webservice.