H2B workers are entitled to file and received refunds as are US citizens. Can they use a 1040ez or do they need to file a 1040NR?

It depends upon when you entered the U.S. are you married or not, and how many days on H1-B you have spent in the U.S.

Single H2B worker entered Feb 2007 returned to Mexico Dec 2007. Will be returning late March 2008 until Dec 2008.