I am not really sure what you want to do with your desktop but here are 3 options (I believe one of them will answer your question)
If you want to remote control your desktop than you can use something like VNC (install the server on your desktop and the client on your PPC -
http://www.cs.utah.edu/~midgley/wince/vnc.html)
if you only need access to files you can do that with an FTP client
(e.g.
http://www.noisette-software.com/)
3rd option is to use something like pocketlance (
http://www.pocketlance.com/) that will allow to access network resources (e.g. shared folders) from your PPC
HTH,
Arnon