Apple recently launched their social network within iTunes. The point of the social network is to find out about new music by following your favorite artists and friends and see what they are posting, what they like, and most importantly, unique, and influential, is showing what you purchased. There isn't much to the service yet, but Apple and iTunes have major potential, especially since they purchased the popular lala.com service that we were big fans of. lala.com was a service that let you "upload" your entire music catalog and access it anywhere you have an internet connection, as well as "purchase" music for streaming rights for a tenth of the cost to download.
Make sure you have the most recent version of iTunes, and check out Ping. There is a relatively small select group of bands and artists available on Ping. Currently the only Christian Hip Hop artists we've found are Lecrae, Trip Lee, Kaboose, and Manafest. You can follow me on Ping here.