Since I read some posts of people having problems with WPA networks and Ambicom cards, in my experience (Debian eabi+Angstrom kernel), I managed to connect to my WPA access point installing wpa supplicant package from debian repositories and installing
http://www.angstrom-distribution.org/unsta..._1.0-r3_all.ipk from angstrom feed.
This package installs binary firmwares for prism chipsets and load them on boot (I had to add something to rc.d If I remember correctly).
I'm going to experiment ZDevil root filesystem + younggun kernel in the next days and I will be more precise.
