Some useful places to find info on OpenWrt, including wireless configuration options, etc. Note that not all options are supported by all chipsets, and some things may only work in the latest release of OpenWrt (the tutorials here are based on an old version that is somewhere in between Kamikaze 7.09 and 8.09).
Supported hardware tables
OpenWrt forums. You will probably get a faster/better answer to OpenWrt questions on their forums vs. here.