[a4ans]

I entered usa in December 2004 as an f1 student and would start a job on opt in September 2009. Is it true that based on 5 calender years I am a resident alien for the year 2008.

If so, would it make any difference in my taxes (fica/social security/medicare) if I start my h1b in October or should I remain on opt till next October.

[MukatA]

In 2009, your income is subject to SS tax and Medicare tax. You will file resident tax return, and can not claim any treaty deduction.

[AtlantaTaxExpert]

The key is what you INTENT will be after the OPT period.

If you intend to apply for a H-1B visa, then you cannot claim "a closer connection" to your home country in order to retain your non-resident status in order to avoid paying FICA taxes. Based on your posting, this seems to be the case.