When you pre order something.. do they take the payment there and then or do they take the payment the day its shipped?

I wanna pre order Gears of War 2 but dont have the money yet and want to get it the day of release before it sells out.
They're supposed to not take the cash until dispatch, but one time they took cash off me despite the fact that it was out of stock.
They usually take the payment when you order it, but that means you get it as soon as it's released.
Schecter C-1 Hellraiser
Ibanez GRG170DX
Peavey Vypyr 75
Fender Princeton 650 DSP w/ Celestion 80w speaker
They take it out when its dispatched, they aren't allowed to deduct it before hand
Ibanez PGM301 signed by Paul Gilbert
Ibanez PGM 500
Ibanez Fireman custom
Saving for a GH100L/VH100R
Orange PPC212 2X12
They don't take it until it's out/despatched.

But play.com are becoming notorious for having problems. Someone made a thread about how they didn't recieve their item for weeks, and last year my friend ordered a DVD and the order mucked up and he had to phone them (students so he had to use a mobile phone and waste loads of credit) and took him ages to get it sorted.