Hi divakar,
A lot of downloads are available now a days, you can try out any of these downloads. The total score of GMAT is 800, It contains 78 multiple choice questions and 2 essays. GMAT needs a lot of practice, the best way to prepare is to take lots of practice tests, so you get used to the format. While searching for my study material, came across these sites offering free practice tests and some good stuff- hope this will help you ……….. Best of luck :)
http://www.examville.com/virtualtests.jsp
http://www.greguide.com
http://www.testprepreview.com/gre_practice.htm