This was probably overkill, but i followed the instructions on http://plugcomputer.org/plugwiki/index.php/Compiling_Linux_Kernel_for_the_Plug_Computer
and cross-compiled the kernel on my Ubuntu VirtualBox environment, also took the following steps:
- applied the patches from http://sheeva.with-linux.com/sheeva/index.php?dir=22.214.171.124%2Fpatches%2F
- copied the .config available on the same website (http://sheeva.with-linux.com/sheeva/126.96.36.199/sheeva-188.8.131.52.config
- changed line:
# CONFIG_ZD1211RW is not set
ran the make as per continued instructions (i skipped all the U-boot related steps as i didn't want to flash my plug)
- copied the zd1211rw.ko file that was produced to the sheevaplug and loaded it with insmod zd1211rw.ko
- verified it was working with ifconfig!
I'm sure there's a way to bypass needing to do a full kernel compile and doing just the driver itself, but it did the trick for me!!!