I have been in the US for 15 months on a extended H2B visa. I had 2 jobs in 2008, 6 months each. Do I claim both back at the same time, or separately?

You claim all your income on one return. For 2008 you will file resident tax return. Read about H1B tax filing: Your U.S. Tax Return: The U.S. Visas (http://taxipay.blogspot.com/2008/08/us-visas.html)