If you only need one device to connect back to your wireless router, you can get a cheap
Linksys WAP54G and set it up in "client mode" (not bridged mode). This will in essence give your wired machine, wireless access. No hacked firmware needed, and should be able to connect to just about any 802.11g wireless AP (or wireless router).
That or the Buffalo. The Buffalo router may be better if you want to connect more than one machine and can find it for cheaper.