The SDK has not been forgotten (although Nokia / Microsoft have done us no favors in terms of keeping it alive ); there are still a few places that have mirrors of the SDK available. Also, TMO user endsormeans has created a "Live ISO" that might be an easier way to get a Maemo dev environment up and running. Here are some links:

This thread discusses how to download the Qt SDK:

http://talk.maemo.org/showthread.php?t=95495

This thread describes how to use the new live ISO:

http://talk.maemo.org/showthread.php?t=95567

Hope this helps!

EDIT: Drat, I'm too slow to the punch, endsormeans has already provided the answer.