:( I forgot to add income of my one w2 (2007) form while filling tax returns for 2008 what shall I do now ?

You will need to file amended tax return. Earlier you do better it is if you owe money by reporting W2 as you will be charged interest and penalty after April 15, 2008.

You will need to file amended tax return. Earlier you do better it is if you owe money by reporting W2 as you will be charged interest and penalty after April 15, 2008.
Can you please eleborate.. amended tax return.. I have already send my 1040 ez by post... what would be the right way to file amended tax return

Amended tax return is Form 1040X.