If you do use zd1211 - few things to note:
1) Last time I checked, the released tar.gz on sourceforge did not work. Use the cvs version.
2) There's also another development branch on subversion:
http://zd1211.ath.cx/
That IS the same project, but the two branches are not fully
merged yet, some patches are cvs only, others svn only
(e.g. - WPA support :-( )
3) The zd1211_ng driver available on sourceforge is supposed to be a
rewrite. It's currently just a skeleton, and currently seems to be
abandoned.