State of Entropy has lots of cool PSP tutorials to create graphics such as backgrounds, text, buttons, etc. The tutorials range from PSP4-PSP7, but you can adapt them for your version of PSP.
Note: I found this site through the Wayback Machine so not all images on the linked pages are visible, but I clicked a bunch and many of them still have the visible images.
Post Codes
PSP Challenges
Smileys
Taggy Me
Tema anterior
Primer 