According to an unsealed criminal complaint against him:

Federal prosecutors have charged Edward Snowden, the man who admitted leaking top-secret details about U.S. surveillance programs, with espionage and theft of government property, according to a criminal complaint that was unsealed Friday in U.S. District Court in Virginia.

The United States has asked Hong Kong to detain Snowden on a provisional arrest warrant, The Washington Post reported, citing unnamed U.S. officials.
The complaint charges Snowden with theft of government property, unauthorized communication of national defense information and willful communication of classified intelligence to an unauthorized person — allegations that amount to espionage in the United States under the federal Espionage Act.

The full complaint is here.

National security reporter Eli Lake notes:

#Snowden appears to be charged under the Espionage Act as a leaker. This is very different than treason as defined by the #constitution

— Eli Lake (@EliLake) June 21, 2013

Glenn Greenwald called the charges “vindictive,” adding:

https://twitter.com/MatthewKeysLive/status/348212353055215616

There’s always this option:

An Icelandic businessman linked to WikiLeaks said he has readied a private plane to take Edward Snowden, the former National Security Agency contractor who exposed secret U.S. surveillance programs, to Iceland if the government grants him asylum.

“We have made everything ready at our end now we only have to wait for confirmation from the (Icelandic) Interior Ministry,” Olafur Vignir Sigurvinsson told Reuters. He is a former director of DataCell, a company which processed payments for WikiLeaks.

“A private jet is in place in China and we could fly Snowden over tomorrow if we get positive reaction from the Interior Ministry. We need to get confirmation of asylum and that he will not be extradited to the U.S. We would most want him to get a citizenship as well,” Sigurvinsson said.