HELP NEEDED!!Apprvd H1B from A.Pending H1B trnsfr from B new offer from C.

I have an approved H1B petition from company A which is valid till 2015. I got a new offer from company B, filed for a H1B transfer and currently working for company B (just one month before) but the H1B transfer is still pending.

Now I received another offer from Company C, which I really want to join.

I have the below questions:

  1. Do I have to wait for approval from company B to port to company C?

  2. Can I port my H1B to company C using company A H1B approved petition?

Can someone who has gone through this or has knowledge about this situation please answer… I am really worried…!