I came to United States to work on 15th Oct 2007 (entered the country on 29th Sep 2007).

Obviously I am a non-resident alien for tax year 2007. Just wondering can I use first year choice and get more deduction on tax?

I will only become a resisent at the end of May 2008 according to the presence test. By that time, the dealine of filing tax already pass...

Appreciate any advice.

You don't get any extra deduction by First Year Choice. This makes you Dual Status and the tax return is complicated.

File nonresident tax return. If you have work visa you can deduct moving expenses.
Read: Your U.S. Tax Return: Moving Expenses

MukatA, thanks for your advice!