Do we still have the tax benefit of buying energy star appliance in 2011 ?
Say for e.g.. If I buy a 2000 dollars energy star refrigerator, and tax rate is 30%, I will save 600 dollars tax regardless of my income level?

It is still in effect but not like last year. Federal Tax Credits for Energy Efficiency : ENERGY STAR How much have you done in previous years, there is a lifetime limit

Fridges were part of state rebate programs, not the tax credit. Most have been used up and are expired.