If you travel a lot and run Windows Media Center Edition, you really should have this application installed.
www.orb.com
Basically it does a authentication between your Media Centre and their servers, you can then simply login remotely - from anywhere in the world to their solution and hit your content.
Imagine that - sitting in a meeting and tapping in to your Media centre at home
Better still, it works even with non-MCE versions of XP, though these must be fully updated.