H4 to H1 , H1 Visa Transfer

[attaluri]

As of now I am in H4 Visa status and recently I got H1 visa approval, so I can work from October 1, 2008. I have my SSN.

I got H1 Visa approval from Company A and before starting work with that company can I transfer my H1 Visa to another company say Company B. There are no pay stubs from Company A. Company A is ready to help me out in this matter if there is any legal provision.

Please help me in this concern.

Lavanya.