I know on the 8100 there is a quick way to lock your device. Can this be done on the 8800? ( apologies in advance if you find this a dumb question!)

Depends on what you mean by locked?

Holding the mute button down, on the top of the 88xx series, will put it in standby so that pushing a button will not do anything.

If you want to lock it from anyone using without permission, Blackberry has a keyboard lock feature.

Wirelessly posted (Verizon 8830: BlackBerry8830/4.2.2 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/105)

Yeah.
I put a lock on my device because of my wife

Wirelessly posted (BlackBerry8700/4.2.1 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/100)

Does she snoop? Or does she tend to mess the B B up when she uses it. If you want a password go into security options and enable password

Wirelessly posted (BlackBerry8700/4.2.1 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/100)

If you just want to lock from in advertantly pressing keys you can also disable dial from homescreen and using the K key be able to lock the keyboard