Notice how I have no tutorials on How To Start Up PSP, How To Save A File, How To Draw A Circle or How To Create A Line. If you would like to acquire the knowledge of these things please read the manual that comes with PSP or go to JASC's web site for support.
Experimentation is the most effective tutorial of all.
This is a quick and easy way to make any shape have rounded corners. I use this technique daily. The infamous lighting effect tutorial. Use this in conjunction with the button mask tutorial. Take the tutorial Suggest a tutorial Lighting Effect 2 A really fast and easy lighting effect that could be mistaken for a PS filter.