I came across these great links regarding multi-touch. I think i am going to need to build a coffee table..
Building the touch surface:
http://www.digitalstratum.com/programming/ftir_build
http://tbeta.nuigroup.com/ - supported by Google SOC
http://hackaday.com/2008/05/20/multitouch-project-roundup/
http://gizmodo.com/391103/full+screen-multitouch-mac-os-x-is-here
http://wiki.nuigroup.com/Tbeta_-_Getting_Started
http://labs.ideo.com/2009/02/11/hacked-rear-projection-tv-into-multitouch-display
http://hackaday.com/2008/05/20/multitouch-rear-projection-tv/
http://hackaday.com/page/2/?s=multi+touch
http://www.softmt.com/