I just announced our just-about-functional rewritten ZD1211 driver on the zd1211-devs mailing list. The driver is actually usable (and reliable!) on unencrypted networks.

A fully usable (WLAN client) driver is now well within sight, we just need to implement connecting to encrypted networks and automatic rate management.

More advanced features (such as ad-hoc connectivity, master mode, monitor mode, …) will come later. Hopefully the community will help us out there.