I am on H1 in US from Feb 2008.
My wife and kid joined me in Mar 2008 on H4(none have SSN).
Now I plan to file taxes for 2008. I will be filing under status as "married filing joinly".
But since wife does not have SSN, I won't qualify for "recovery rebate credit" of $1200.

Is there any way wherein I can first file as stutus "single" and get the "recovery tax rebate" of $600 and later amend the return to add my wife and Kid to get the dependent benefit ?
Thanks in advance for your help

If you are married you must file as either Married Filing Jointly or Married Filing Separately - you may not file as single, sorry.

Yes, you can file as married filing separately, and get recovery rebate.
Then file amended tax return as married filing jointly.
Read Your U.S. Tax Return: Filing Status for Married