Well HomeBrew Sorter GUI beta 4 is a EBOOT app that you put in your GAME folder and run from your PSP.
Game Categories is what is called a PSP plugin. Plugins are programs that add more fuctionality to your PSP. It is different in the sense that you don't exactly run it like you would an EBOOT app. It's more of a program that when enabled is running in the backround on your PSP. Also the installation method is different.
If you would like I could type a quick tut explaining how to install the Game Categories plugin. If so though I would need to know what firmware you are running. I haven't kept up with the latest CFW releases so I'm not really sure what the latest PRO release is up to now.
Here is a example of Game Categories and what it can do. This version probably isn't compatible with you CFW so I wouldn't download it but it's a good example none the less.
Spoiler warning: