I was on OPT from Dec 20th 2007 till Setptember 30th 2008(PHASE-1) and changed to H1 from October 1st till date(PHASE-2).

Now I understand I have to file the 1040NR form. I don't have Social Security and Medicare tax for PHASE-1(and nothing was withheld in this period) and the tax for SS and Medicare was withheld for me from PHASE-2.

So on the 1040NR where do I have to enter the Medicare and SS tax info mentioned on my W2 form?

Any advice on this will be truly appreciated.

Thanks.

If your are single, you will file non-resident tax return Form 1040NR or 1040NR-EZ and Form 8843. SS tax and Medicare tax info does not appear on the tax form.
Read: Your U.S. Tax Return: U.S. Tax Filing Requirements for Non-Residents (http://taxipay.blogspot.com/2008/03/us-tax-filing-requirements-for-non.html)

Just to make it clear... Am I supposed to ignore the SS an Medicare Taxes completely and not mention anything on any forms as no taxes were withheld during my OPT period even though I paid for it during my H1-B period?

Thanks.

yes.