When is the starting date to work on H-1B?

Regarding USCIS Updates H-1B Cap Count 10/30/09, if the employer files my H1B petition immediately, (1)how long the H-1B approval takes and (2)when is the starting date to work on H-1B? As far as I'm concerned, the H-1B petition quota had usually been reached on APR 1 and the starting work date is Oct 1. But this year is different since the quota has not yet been reached. My employer would like me to work ASAP, so I would like to know if they file my H-1B petition now, can I get approved and work before Oct 1, 2010? (I have a Master's Degree from USA.)