You may want to hold off on buying that Linksys WRT54G until Linksys hammers out a few more bugs. I've got a laptop with a built-in 802.11b function that works perfectly with a SMC Barricade (with wireless) but refuses to work with the 54G. I can get the laptop to "see" the AP and can even sniff pings from the laptop on the desktop machine. However, the replies are not going back via the wireless interface.
I'm going to abuse the 24x7 customer support line this afternoon. I'll keep you posted.