• http://www.flamingspork.com/blog/?p=338 lists a way to build the driver.

  (that's rt2500 which possibly isn't the same thing, and I found it quite hard to follow)

• http://lists.ubuntu.com/archives/ubuntu-users/2004-October/008665.html implies it should be in Hoary anyway!

  (But it doesn't appear to be)

Get the sources and unpack them somewhere appropriate (I'll assume /usr/src/)

Then, as root;

  apt-get install gcc kernel-headers-`uname -r`
  cd /usr/src/rt2400-1.2.1/Module
  make && make install
  echo "alias ra0 rt2400" >> /etc/modules.conf

After this you should be able to set up ra0 under /etc/network/interfaces, the same procedure as any other WiFi? card, but you might also want the ra2400 utilities installed.

(Tentatively, this should involve

  apt-get install (whatever package provides "qt-x11-free-3.1.1 or later" ?)
  cd /usr/src/rt2400-1.2.1/Utility
  ./Configure && make && make install

I'm still working on this part)