Hi
I came to US on 24Aug08 on H1B Visa with family (Spouse and daughter).
I need to file income tax for the year 2008, but not sure under which category I need to file the tax, So please guide me.
My spouse and daughter dont have ITIN.

According to the information you've provided, you are a non-resident for 2008.

If you become a resident in 2009, there are some elections open to you in terms of being resident for all or part of 2008. This would however mean including any foreign income for US tax purposes and claiming a foreign tax credit for foreign taxes paid.

Thanks for your reply.
can I (Non-resident align) file tax as a married filling jointly

Choice 1: You can file non-resident tax return. Your status is Married Alien.

Choice 2: You can file resident tax return as Married Filing Jointly. You will have to wait for 4 months in 2009 to file your tax return till you meet the Substantial Presence Test (of 183 days) in 2009.

You must both declare your worldwide income for 2008. If you have any foreign income, and paid taxes in the foreign country, then you can claim foreign tax credit.

You will complete forms W7 (application for ITIN) for your spouse and children and attach with your tax return.
Read about H1-B tax filing: Your U.S. Tax Return: The U.S. Visas (http://taxipay.blogspot.com/2008/08/us-visas.html)

Thanks for your reply.
can I (Non-resident align) file tax as a married filling jointly

You can't file as a NR and file MFJ.

The only way that you would file MFJ is if you make some additional elections which would necessitate you including income earned in the foreign country (in the year that you came to the US) and claiming a foreign tax credit.