Ok, so I just discovered the "Change lock background" thing in WOQI and love it. I tried an image from everythingpre (yes, I know I'm betraying PreCentral by going there...i'm sorry =P) and it looks very nice with the theme I'm using. Here's a screeny:
http://i36.tinypic.com/2ebco0n.jpg

I'm using this theme:
Original Blue Theme Palm Pre Theme @ PreThemer

I really liked it so I thought I'd post it =)

(just in case someone bugs me about it, I dont take credit for making the picture, or the theme, i just put them together =P)