Driver's License in the States

The Driver's license test generally has 2 parts. 

Knowledge and the ACTUAL driving test

If you have an Indian license, take the same along with the following documents

1. Passport
2. I-94 printout
3. Letter from employer stating that you work there
4. SSN- Details on how to get one is in the previous post.

For the knowledge test, you can practise online by doing practise one's according to your respective States. You can get few here (http://driving-tests.org/) In Ohio, the test has 40 questions and you just have to get 75% of the questions to clear the exam and then schedule your DRIVING test.

Best of luck!

P.S.- I read the manual and did the above questions. Most of the questions just need plain common sense answers :) So it really won't take too much time.