Can I do this? I can't figure it out and can't find any related posts in archives...

I have:
2- Windows XP Pro PCs (1 laptop 1 desktop)
1- Linksys WRT54G Wireless/Wired Router

I want to:
Use built in 56k modem on laptop and USB wirelessB box to share internet with Desktop through the WRT54G... is this possible or not?


For some reason I can't get any basic connectivity (ping) through the router

PPPPPLLLLLEEEEAAAASSSEEEE!

I can wire the network but I'd rather not.