Thanks for your replies guys. Much appreciated. I wil only be executing this strategy on blue chip stocks. I pressume that when the underlying stock starts to drop I can still close out the position at a profit as the option starts to decline as well. No need to hold it until expiry.
No offence mate - but that's a really, really basic question (you can close out of the position by the way, but not necessarily at a profit) and perhaps you should seriously consider spending some time trading a simulation account before you jump head-first into this.