Most bmws 99+ use the Ibus, there are plenty of interfaces available, but the one to go for is made by a guy called Rolf Reseller, that has the best compatibility with all of the Ibus commands.
As for the yahoo group if its hack the ibus, the group hasnt had any new members for a while, and people dont get replys from the admins that setup the group, the main site we all used has recently been closed as well, which had all the codes, just do a search for 'ibus' and tons of info will come up, from software (which can control the steering wheel buttons, as well as lights, windows, cruise control etc) to interfaces.
