The Anti-Injunction Act issue is under consideration because of a ruling in Liberty v. Geithner that essentially deemed the individual mandate a Constitutional exercise of Congress's taxing power.
In my view, the worst possible outcome of this Supreme Court battle is that the Court call the mandate a tax. Everyone recognizes that it is NOT a tax (including the acting White House budget director), but a ruling to the contrary would delay a ruling on the health care law until as late as 2016.
If you Google "Anti-Injunction Act", there are many web pages of analysis devoted to it. Here is the partial text of one of them:
"The most sensible reading of the Anti-Injunction Act’s text and purpose is that it does not apply until the authority to assess and collect taxes has come into being, just as it does not apply after that authority has been exercised."
The authority to tax does not come into being until 2015 ...