Hi,
I'm on H1B for last 1.5 years and a Resident Alien (I met the Substantial Presence Test). I got married in Nov. 2008 and my wife is not yet moved to USA (filed for her h4).
Can I file my tax return with MFJ status once she reaches here or it will be Single status only?
Thanks in advance.

You can file jointly with her. She will have to include her worldwide income on the U.S. tax return. She will need an ITIN. Include Form W-7 and applicable documents attached to the front of Form 1040 and send to address in the instructions to Form W-7.

The best identifying document to submit with the W-7 is a notarized photocopy of her passport.

If you live in India, getting such a photocopy properly notarized is difficult (the IRS will only accept copies certified/notarized by either the U.S. Embassy or a U.S. consulate office). Hence, it would probably be better for you to wait until she arrives in the U.S. then get the passport photocopy notarized at your local bank or at a local IRS office.