I purchased Locktopus ($2) as it seemed to have good integration with the iOS 4.1 springboard. Unfortunately, I have MultiIconMover installed, and my finger can't toggle the lock...it just toggles the red-check badge. So...I uninstalled Locktopus and purchased Lockdown Pro ($1.99). From what I've seen so far, Lockdown Pro has more options than Locktopus, and my old locking program mAdvLock. I'm very satisified with Lockdown Pro, and am looking forward to the planned updates (lock complete folders).