I graduated in December 2007 and started working full time on opt from January 2008. Do I have to pay social security and medicare taxes for the income in 2008? Is there any tax filing software that anyone recommends? Can I use turbotax or cintax?

Thank you
Sagar

1. When did you enter the U.S. on F1?
2. When did H1-B start?

I entered us in September 2006.
My h1b started jan 2009

Sagar

For 2008, you had F1/OPT.
On F1/OPT you are exempt from residency for 5-years. You must file non-resident tax return Form 1040NR or 1040NR-EZ and Form 8843.

Your income is not subject to FICA taxes but you must pay federal and state income taxes. On your OPT income you will get deduction based on tax treaty between the U.S. and your country. If you are from India, as per tax treaty, you will claim standard deduction of $5,450 instead of itemized deduction.
Read: Your U.S. Tax Return: U.S. Tax Filing Requirements for Non-Residents

Most of the softwares do not do nonresident tax return. It can not be efiled. You must file paper return.