Since I got my XO laptop, I’ve been frustrated by its incompatibility with WPA encryption for wireless connections, since I have my home network set up for WPA. Aside from reducing the security, changing it would mean changing the settings of my wii, Airport Express, and Slingbox, which isn’t too convenient.
Digging around in the OLPC Wiki, I found that an unofficial software update to build 653 is available. I was able to get the XO online by temporarily turning on internet sharing with no encryption on my Mac Mini to install the update. After updating, the XO will now connect easily to my Airport Extreme and is able to go online