SpotLock is a new jailbreak tweak that allows you to lock your iPhone simply by swiping over to the place where Spotlight search normally resides. Granted, this tweak will totally eliminate the ability to use Spotlight search, but I believe the popular consensus is that many of you don't use Spotlight to begin with.
Of course, a quick press of the sleep button at the top of your iPhone is the quickest way to secure your iPhone from a software perspective, but SpotLock is an interesting way to break the monotony and switch things up a bit...