Current Situation: Labor Approved, I-140 Approved 6th April 2011, H1B valid till Sept 2011 (Completes 6 yrs)

Questions:

Have an full time offer with the client, Can I take the offer( transfer H1 and apply for new GC) any implications?
or Do I need to wait for sometime since 140 is approved recently

WIll I get 3 years extension for H1 (with new client or company.)

In case I go head with client offer and during the transfer,what if my previous employer revokes my labor/I140...What will be my status.
Does the new employer need to start GC immediately.

what if there is mismatch in the skill sets for new PERM application with new company and old labor application.