Re-entering U.S for work after Visa expiry

Hello,

I have worked on H1 B for 6 years and my Visa is expiring in Aug 2012. I’m planning to get new Visa L1 A from India and wish to re-enter U.S. How much gap is allowed for outside U.S stay so that one can start working again by coming back to U.S.

Thanks,

Becky