My friend was employed in INDIA from 1st April 2008 to 31 Dec 2008.
From Jan 2009 he was shifted to parent company in US.

From 1st Jan 2009 he is on US company's payroll and getting salary there and are paying all US taxes.

Now for India taxation for FY 2008-09 he is resident and ordinary resident and this global income will be taxable.

Question : Whether his three month US salary will be taxable in India in FY 2008-09?
If yes whether he can claim taxes paid in US in his India Tax Return?
If yes how we will calim credit of US taxes in India i.e what will be the calculation.

Thanks for help
Sorabh

He may claim a credit for US tax paid on his Indian tax. See DTA US/India Art 25(2).

Find a professional preparer in India to compute the credit. We do not do that here.