Since a long-term solution to the Alternative Minimum Tax was not reached again this year, it needs yet another one-year "patch." This patch will prevent the AMT from reaching some 20 million lower-upper class Americans.

The patch will be costly, about $50 billion. The Democrats want to pay for it by raising taxes on investment managers in the private equity, hedge fund and real estate industries. Right now these managers receive their income in a manner that allows them to be taxed at lower rates, like 15 percent, instead of the normal income tax rate the rest of us pay. But this is unacceptable to the Republicans.

Rather than paying for the patch, they prefer to do what they've been doing all along--borrow it.
http://thehill.com/leading-the-news/senate-gop-coordinates-amt-attack-2007-11-10.html

Does anyone know if that is 100K combined or single?

I think that who gets hit by the AMT and who doesn't is a factor of a lot of different things. If you have a big home mortgage deduction, a lot of credits (i.e. a lot of kids), and other items then the income level at which you can be hit gets lower. So there's no particular level at which you can say everyone will be under the tax--it depends on the individual circumstances.
I understand that income tax preparation software routinely checks for the AMT.