I found a post about this in the "search" section of this site but no one responded to it so I was wondering this myself.... is it possible to use like XBConnect or Gamespy? well maybe not gamespy because I heard they have "lag" problems...
It's possible and quite easy... you only have to plug your xbox in network with your PC and share the internet connection then log with xbconnect or gamespy (gamespy works quite well)