I was working in US on E-3 visa before H1B. Which means I entered USA earlier. When does my 6 years clock starts?
In that case, your 6-year clock begins to run on the date you converted (changed status) to H-1.
Can someone apply for E-2 visa ,who now residing in USA,is it possible and how long it will take?
Yes, they can. I believe premium processing is available for E visas. If you opt for that, it could take a few weeks.
I am married to a permanent resident of America, and have filed for a spouse visa (I130) in Sept 2010. Is it possible for me to apply for the E-3 visa with the spouse visa being processed, or does it demonstrate dual intent?
E-3 is not a clear dual intent visa. BUT, govt. tends to lean in the direction that they will permit dual intent as long as you clearly intend to leave if not permitted by law. My suggestion would be to avoid testing the E-3 limits in our current environment.
The Department has posted new Frequently Asked Questions (FAQs) for the H-1B, H-1B1 and E-3 Programs.