I just downloaded this software. Its pretty interesting.
If your using PdaNet you should upgrade to 3.0 first so that the two applications can run together.

I downloaded it from JuneFabrics http://www.junefabrics.com/pdareach/

Ever dream of controlling your Palm Handheld directly from your PC? With PdaReach now it is possible! All you need to do is just connect your PDA to your PC with the HotSync cable, and PdaReach will take care of the rest to bring you the what-you-see-is-what-you-get experience live on the PC monitor.

Somehow I can't get it to show me doubleview for the treo model but the other ones work