How to change lock screen image on 3g

[yaas]

Hey guys!
This myt be a bit silly,but can someone please help!

I want to change the lock screen image.At the moment its got the "Globe" on,but I want 2 know hw u can change that.

Also does any1 know where i can find an apps to change the theme on iphone 3g?

I've got Cydia on & I am sure there are apps somewhere.I just need some guidance.

Thanks.

[Rubwens]

U can change your lock image from Settings -> General -> Wallpapers.

[yaas]

U can change your lock image from Settings -> General -> Wallpapers.

I know that already,mate

But how do I go about 2 get new wallpapers as the 1s on the iphone are just rubbish!