Follow these instructions

Download the latest driver from ASPj's WiFi Page: mdk3, rt73, rt2570 and other aircrack-ng experiments
As of 2009-04-16, the latest driver is 3.0.2
http://homepages.tu-darmstadt.de/~p_...-3.0.2.tar.bz2

Code:
ifconfig rausb0 down
airdriver-ng remove 31
tar xvjf rt73-k2wrlz-3.0.2.tar.bz2
cd rt73*/Module
make
make install
modprobe rt73
ifconfig rausb0 up
Getting these results

root@BT4PF:~/rt73-k2wrlz-3.0.2/Module# make
make: *** /lib/modules/2.6.30.9/build: No such file or directory. Stop.
rt73.ko failed to build!
make: *** [module] Error 1

Then if i try it after ive made the directories i get

root@BT4PF:~/rt73-k2wrlz-3.0.2/Module# make
make[1]: Entering directory `/lib/modules/2.6.30.9/build'
make[1]: Nothing to be done for `modules'.
make[1]: Leaving directory `/lib/modules/2.6.30.9/build'
rt73.ko failed to build!
make: *** [module] Error 1