If not, you need to apply for 2007 H1B, which starts 10/1/2006. And you can submit application on 4/1/2006. But you can still name your start date. For example: you start your F1 OPT on 12/15/2005, the OPT exprires on 12/14/2006. Then you have two choice: a, submit on 4/1/2006 for stat date of 10/1/06, or b, submit on 6/15/06 for the start date of 12/15/06.
In a, you will get it, but waste a little bit of your OPT time. in b, you will use all your OPT time, but the quote might be gone before ou submit, which is possible. So you decide.