According to Pro Football Talk, he is:

http://www.profootballtalk.com/rumor...

A league source tells us that the contract that eventually will be signed by linebacker Zach Thomas with the Cowboys carries a $1 million signing bonus and a $1 million base salary in 2008.  Thomas also can earn up to $1 million in incentives.

Though it's technically a multi-year deal, the structure will make it essentially a one-year relationship.