Alphacon is a nice free tweak available on Cydia. It simply enables you to apply your own alpha transparency settings to your icons, folders, switcher, and dock. Nice and simple. Does exactly what it says on the tin... The tweak comes with a basic set of settings to fiddle with... And in this example you can see a nice subtle application of transparency to my icons and folders in comparison to those on the dock.... The tweak seems to play nicely with all the major springboard tweaks such as Winterboard, shrink, iconoclasm, switcher mod etc. That's Alphacon! Have fun messing with your icon transparency.