If you're rocking an LG Optimus S on Sprint, you MUST check out the LG Optimus S Control Center from Android Central Forums member drewwalton19216801. Behind the long name is an easy-to-use Windows application that does a little bit of everything you need to hack your Optimus S, without fiddling with the prompt or trying to remember cryptic commands.
Using what the developer has dubbed "Android Automation Technology" (AAT) the current version will root your phone, unroot your phone, and install your choice of recovery kernels. There's also the magic of "No Stupid Stuff" -- which prevents the application from doing things it shouldn't -- like trying to swap recovery kernels without being rooted or trying to unroot when you shouldn't.
This looks like an awesome beginning for a tool that will do it all. Some of the features planned for a future release are things like removing/restoring Sprint ID, Switching launchers, and possibly even switching ROMs and kernels. Very nice work Drew, you've made a great little phone even better. Go check it out in the Android Central forums!