Want the good news or bad news?
Good news:
If you update to Mountain Lion from Lion, VMWare 4 Fusion works.
Bad news:
If you do a clean install of Mountain Lion and try to reinstall VMWare 4 Fusion, it is not compatible.
Although. I have the first 4 version so, maybe the next upgrades might. I'll contact VMWare and see, otherwise. I can't install it again. :|