Slide2Unlock's new version works as Colonel describes. By default he has the close on exit option set to off, so that the ilock program is always running, and therefore is invoked when you press the power button or the phone is left idle for a period of time. If you change that close on exit option to on, then that behavior will not occur. Also, he has recently moved all of the settings to the registry. I prefer the .ini as it is easy to find and change, but the registry may read faster, and I understand this newest version is pretty fluid.
Link to newest version:
http://forum.xda-developers.com/show...t=slide2unlock