I'd recommend to use the ndiswrapper with this chipset.
I have tried in about 5 different distributions. The vendor's driver does not work correctly. ndiswrapper has worked every time. The only difference between the distros is the way you specify to start the card at start-up time. Unfortulatelly debian install did not identify my HDD correctly and I haven't been able to try it. but I have tried in other debian based distros (e.g. knoppix)
The compilation has always been clean and easy. The instructions on the ndiswrapper project installation page are clear. Just follow them step by stem regardless of your distribution:
Here is my entry in the Hardware compatibility list
sometimes the link to the project page is slow, so here is it in a nutshell
Download the lates version of the ndiswrapper source
Get the windows drivers for your card (you need the .inf and .sys files). You can find them in the cd provided by the vendor or on your vendor's web site. Make sure that both files use the same case (e.g. both RT2500 or both rt2500)
(If you need the source and the drivers let me know and I can upload them to a shared location. I am using the same card)
then do the following as root
tar -xvzf ndiswrapper-xxx.tar.gz <--- xxx is whatever version you downloaded
cd ndiswrapper-xxx <- xxx is whatever version you downloaded
make && make install
cp ~/rt2500.* ./ <-- assuming that you copied the drivers to your home folder
ndiswrapper -i rt2500.inf
ndiswrapper -l <--- it is a lower case L. this command will show you if the driver has installed correctly
iwconfig wlan0 mode Managed <--- or whatever mode your network is using
iwconfig wlan0 key restricted XXXXXXXX <-- the hexadecimal of your network key in case your network is restricted
iwconfig wlan0 essid aaaaaa <--- the essid of your network
ifconfig wlan0 up
dhclient wlan0 <-- different distros have different utilities for the dhcp discovery, use the one appropriate for your distro
ndiswrapper -m <---- writes the configuration for modprobe
You should be able to use your network now.
The next step is to configure it to start-up at boot time. As I said before different distros do it differently. I' ve used system-config-network in some in some others I've had to edit some /etc files.