I'm not sure about ur case. However I just know that there is a sixty-day grace period in F1 status. This means if ur OPT is ended up after Aug 01, 2007 (for example Aug 15), and an H-1B petition can be filed for you before Aug 15, 2007, and you can remain in the U.S. and then you will automatically be in H-1B status in October 01, 2007. You must discontinue work from Aug 15, 2007 until October 01, 2006 (since your OPT will have expired) but you can remain in the U.S.