Boiling down some of the legalese, the charges (if any are filed) will be "conspiracy to knowingly present a false and fictitious claim upon or against the United States, or any department or agency thereof in violation of USC 18 (secs. 2, 371, 1036, 1343, 2318) and USC 49 (secs. 46314 and 46316) and 49 CFR (secs. 1540.103 and 1540.105)" (edited for brevity).
Sparr0 writes, "The FBI has raided the home of Christopher Soghoian, the grad student who created the NWA boarding pass site. Details can be found on his blog including a scanned copy of the warrant. The bad news is that he really did break the law. The good news is that Senator Charles Schumer did it first, 19 months ago, on an official government website no less. The outcome of this trial should be at least academically interesting. At best, it could result in nullifying some portion of the law(s) that the TSA operates under." Read on for Sparr0's take on what laws may apply in this case.