there are products like drachen’s link from all the major players, linksys, netgear, dlink, etc…some that are JUST attached storage interfaces (linksys comes to mind) might be the better solution if you already have a router/switch in the mix.
also, might consider some of the wireless NAS options out there…no links off-hand, but IOMEGA comes to mind, they just released a 1tb device that is a wireless NAS, print server, media server (if you have a media device attached to your network)...pretty nice, but pricey at around $900. But, IOMEGA has some more low priced options for around $250.
Chris