WiFi adapters for the Raspberry Pi
A few months back I bought a couple of cheap USB WiFi adapters from DealExtreme. Today I finally got around to try them on the Raspberry Pi. Of the three adapters, two works both on a Fedora 17 64 bits based desktop as well as on the RPi. Notice that they both seem to contain the same chip, and indeed reports the same vendor and product ID. The last, the EDUP device, does detect available WiFi networks, but usually does not establish a connection (the very last time I tried, it suddenly did). I suspect it might be a USB power issue, since it also "crashed" the USB hub on the desktop, causing the keyboard and mouse to temporarily disconnect. Here are some notes which might be related. Of the three, the one with antenna is fastest at establishing the connection, but the other small adapter also gives good transfer speed; around 3.6 Mb/s seen today, but I expect it can go faster.
For other devices supported by the RPi, see the the Embedded Linux WiFi page, and also Element 14's WiFi testing page.