I transferred from OPT to H1B in Oct07. I want to file dual status so I can get back some money that was withheld for SS and medicare. Can you please list the forms and steps I need to take to file that? I want to do it on my own. So.. do I start with 1040NR?

Secondly, how do I calculate how much social security and medicare was withheld for the months I was on OPT? On the W2 its just one amount for the entire year. Do I take the amount, divide it by 12 and multiply it by the number of months I was on OPT?

Thanking in anticipation,
Shaaka.

You will file as nonresident alien. No need to wait for a few months to file as Dual Status alien.
You can still get FICA taxes withheld during OPT. You will file form 843, which is filed separate from your tax return. Use simple arithmetics to calculate your income during OPT (yes you divide and multiply... use days instead of months) and then the FICA taxes.

Thanks for your prompt reply... so are you saying that I should only file a 1040NR and fill it out for the entire year with the numbers reflected on my W2 but file an additional form to request back SS and medicare withheld for the time I was on OPT?

Thanks.

Yes, that is right but the additional form is not filed with your tax return.