IDEO has a new lab blog that catalogs some of their projects and experiments, here’s a multi-touch display… They released the code for the FTIR server and the Flash API here if you want to check it out

At IDEO we’re all about building to think. Learning from books and websites and product demos is cool, but we think the really good stuff comes when you get in there and start messing around for real.

In the case of multi-touch interfaces, that meant building a system we could start prototyping on. What we wanted was:
-a multi-touch display large enough to facilitate use by several people at once
-an API for flash that would let us quickly prototype multi-touch interfaces and applications

It took us about 5 weeks to get everything together. Kyle, one of our all-around gearheads, had already been building a drafting-table-style FTIR system in his garage which helped kick-start us.