I have Aerofly Pro and it works great with XP. Go to the bottom of the page and do a search for the sim you like, you can read what every one here has to say about it. Here’s a post I made a while back after buying Aerofly Pro.
http://www.rcuniverse.com/forum/m_10...tm.htm#1085143

And here's all the other sims.

Aerofly http://www.aerofly.de/

FMS http://www.netpackx.com/html/fms_interfaces.html

Great Planes http://www.realflight.com/

RC Plane Master http://www.realitycraft.com/index.htm

Reflex http://www.hobbico.com/reflex/

Ripmax http://www.ripmax.com/FS_Simulators.html

Dave Brown RCFS http://www.dbproducts.com/