I don't know of any distro including a driver for the Zydas. But I have downloaded the drivers from zd1211.ath.cx and they seem to work quite well with kernel version 2.6.14.
You can try them also with your kernel version (whatever it is). All you need is to install your kernel source, untar the driver, cd into the directory where it unpacks and do a "make" and "make install".
After that you can do a "modprobe zd1211" and control results in your /var/lib/messages as well as via "lsmod".
So far, so good. I personally can't get my USB WLAN to work either. Driver installs hasslefree but "iwlist wlan0 scan" does not show my Access Point. Instead he shows me some APs in my neighbourhood, but my own seems not to be there. I have it set up with WPA-PSK, which works nice under Windows XP but seems to make him disappear under Linux. Its independent whether I have wpa_supplicant running or not. Trying to set up my wlan0 with iwconfig wlan0 essid "my_ssid" just shows my errors in /var/log/messages that this ssid is not known (or something similar).
Does anybody have an idea?
Thx in advance