In May there were none.
For the heck of it, compare the one item represented by claims on both FX and FreeMarket’s demo: Gas$3 and $3 for a gallon of gas respectively. The FX claim is trading lower (about 30 versus about 35) even though for it to pay off gas must reach $3 by 2005-12-26 while the FreeMarket demo claim pays if gas reaches $3 by 2006-08-18.
FX is still the only site with remotely interesting claims. Hopefully all these packages will directly support conditional claims one day soon (Zocalo has plans) and the sites that use them will get more interesting as a result.
Update 20050830: The first sentence above is wrong. Chris Masse’s list reminded me of Peter McCluskey‘s U.S. Idea Futures Market from 1999 (I didn’t realize until now that the source has been available). Check out USIFEX’s excellent FAQ on What are conditional claims and how do they work?