Nice. I've been messing with a very old laptop, trying to turn it into a media center that I could stream from my desktop PC. KMPlayer is what I was using. It's very nice but doesn't have the ability to customize. I'll be checking this out.
Well, "media portal" is a fork of "XBMC" ( http://xbmc.org/ , http://en.wikipedia.org/wiki/XBMC )...
Media portal can only run on Windows OS with x86 and x86-64 processor...
XBMC can run on the following OS : Linux, BSD, Mac OS X ( Snow Leopard, Leopard, Tiger ), Apple TV OS, Windows, iOS, first-generation Xbox, and MeeGo ( in development )... with the following architecture : ARM, PPC (PowerPC), x86, x86-64, and MIPS architecture ( in development )... "XBMC live" is fun : a boot CD or USB memory stick for have it with you everywhere...
Not sure that "media portal" or "XBMC" will run smoothly on your old laptop... but you have plenty of XBMC fork... by example, OpenELEC ( http://www.openelec.tv/home/menu/what-is-openelec ) is more for light end computer... only a basic OS with the Media center... not other application...
For next year, a other fork is plannet to be released for light end system... it is called "iConsole" ( http://www.iconsole.vg/wp-content/uploads/2011/05/iConsole-MeeGoSF.pdf )...
For the curious, two other XBMC fork :
- Plex : http://www.plexapp.com/
- Boxee : http://www.boxee.tv/ ( click the "make a boxee" )
The only problem with open source is that you have to much choice ( and bad documentation )... but if you seek something very specific, you have more chance to find it that with commercial software... pretty sure that there is somewhere a open source geek who try to find a way for play movies on the tiny LCD screen from his high end washing machine !!!