My New Crazy Project

I, being of the restless sort, am wont to fill my free hours with little projects.  My Dad is this way, and I always thought it was amazing how he could teach himself to do just about anything.  Well, one project is behind me, and I have another one before me.

Have any of you seen the Apple TV.  The little pretty silver box that streams music and video content from all of the computers in your house to your television.  Well, I sort of want to make a home made Apple TV on steroids.  The other day, I downloaded Boxee, a free program for Mac OS X that is based on the Xbox Media Center.  Boxee basically accesses and plays all of the entertainment content on my computer, a task that can be done by the built in Front Row application.  But where Boxee excels is that it connects to a bunch of online content.  You can sit in twenty feet away from your mac and use your apple remote to go through the library of free tv at Hulu or watch videos from CBS.com.  You can watch Flickr or Picassa slide shows and listen to radio from last.fm.  

What I want to do is build (or cannibalize) a computer that 1)runs Boxee, 2) is hooked up to both macs on my network and can access there content, 3)has all of my dvds burnt on to it, and 4) connects to my TV.  Maybe in the future I will get a card for it and use it as a Tivo.

Now all of those goals are easily accomplished accept for #4, which is going to require the purchase of a good video card.  The problem is my tv is seriously old, in fact it is a hand me down from my grandfather, and I don't have the cash for a new one.  So I need a way to hook up a computer with a good card to a TV with only a composite RCA connection.  But I think I can get it done.