Yes, that still works, but only on already running apps, of course.
Some misc answers:
My understanding was that it took an extremely large amount of development time, and almost nobody paid for it; they tried several different ways of making money with it, none of which worked, and finally gave up. This is also the answer to the oft-asked “Eudora was the greatest mail program ever, why hasn’t anyone cloned it?” question.
All Macs shipping today come with Lion, according to Apple. If it was boxed before Lion shipped, there should be a slip with it that has a free download code.
This is causing great consternation on the Interwebs, and I doubt it will go very long without a better solution, but for now you can fix it by write-protecting the file the OS uses to save the state in. Instructions are here.
You can also use the keys you’d use to switch desktops NOT in Mission Control to switch them in Mission Control. You set these in System Preferences->Keyboard->Keyboard Shortcuts->Mission Control rather than in the Mission Control preference pane, for reasons which I’m sure make perfect sense to someone who’s not me. (I use control left arrow and control right-arrow)