Lots of publicity over the SC child porn decision, but it is really pretty meaningless.

WASHINGTON (Reuters) - The U.S. Supreme Court on Tuesday struck down a federal pornography law that makes it a crime to have computer-generated pictures that look like real children engaged in sexual acts, ruling the law violates free-speech rights.
http://news.findlaw.com/news/s/20020416/courtpornographydc.html

But the technology does not yet exist to make computer-generated pictures that look like real children. Ashcroft's main argument is that some hypothetical defendant might hypothetically try to evade prosecution in some future child porn case by claiming that it was all computer generated.

I thought Thomas's brief opinion made the most sense.

the law in question
http://caselaw.lp.findlaw.com/scripts/ts_search.pl?title=18&sec=2256

SC opinion
http://laws.findlaw.com/us/000/00-795.html