Winterboard - Give your iPhone or iPod Touch a graphical overhaul!
Springtomize - Tear down the walls
Dreamboard - DreamBoard lets you take control over the homescreen of your jailbroken iPhone.
Lockinfo - You can find this app in Cydia - Tweaks.
IntelliScreenX - Need to know where your next meeting is? Do you have any new email?
Cylinder - Sexy homescreen icon animations