Naw, this isn't a 10th Amendment issue. The bill doesn't attempt to force the states to do anything. As somebody mentioned above, the individual mandate contained within the bill is a Commerce Clause issue. In addition to being a Commerce Clause issue, it is also a Taxing & Spending Clause issue, which is likely where the mandate will pass Constitutional scrutiny.
With respect to the Commerce Clause issue, it is difficult to say whether the Supreme Court will add this bill to the very short list of congressional acts that have been ruled as overstepping the power granted to Congress under the Commerce Clause (see U.S. v. Lopez) or whether the Court will find that this is yet another permissible regulation of interstate commerce in a long history of permissible regulations of interstate commerce going all the way back to the nation's founding. The Court rarely slaps Congress on the wrist on Commerce Clause grounds but you never know, this could be one of those rare moments.
If it's a 5-4 vote and the swing vote comes down to Justice Kennedy (which seems to be the Court's m.o. lately) then it's notable to observe that J. Kennedy tends to come down on the side of Justices who believe that Congress has broad powers under the Commerce Clause (see Gonzales v. Raich). So it's likely that the health care bill will be upheld as Constitutional.
However, there are certainly good arguments on both sides of this debate.
The 10th Amendment came up in the New York v. United States case where the court said that you could not tell the State how to spend resources regarding nuclear waste disposal. The same thing happened in Printz v. United States where the Fed could not force local police to enforce the Brady Bill. There were some other cases that I can't find that said the 10th amendment does not really mean anything though and it seems up in the air. I am not real sure how the health bill works, but I was under the impression it required states to direct resources towards the bill without a choice.
I could definitely see a commerce clause argument come up. I agree with Hamilton on that it should be given a bit more clarity although it is a great way for Con Law Professors to give Exams .