Yesterday, Homeland Security served Dwolla with a "seizure warrant" for the account held by Mutum Sigillum, otherwise know as Mt. Gox, which is based in Tokyo and therefore out of US jurisdiction. Dwolla is still operating and individual accounts are fully functional, but any pending transfers to Mt. Gox from account holder's bank accounts will get no further than Dwolla. It will be interesting to see if any Mt. Gox account holders lose dollars in this mess.
The Mt. Gox USD/BTC prices over the last week or so have been weirdly stable, until this news broke, and then briefly dropped from $115 to $103, but is currently back up to $116.
Other dollar portals into Mt. Gox exist (I only used Dwolla), but expect continued proxy attacks on the weak links in the bitcoin economy, especially those businesses who depend on the traditional banking systems.
I guess it speaks well of the underlying bitcoin architecture, that it appears to be resistant to direct attack, but there's no telling what lies on the road ahead, so don't invest anything you can't afford to lose forever. I moved most of my remaining bitcoin off Mt. Gox, leaving just a few coin and dollars to mess around with, as I don't trust them to be able to stave off interference, government or otherwise, indefinitely.