[What is ChickHen?]
ChickHEN works as a homebrew enabler for all PSP models (1000, 2000 and 3000) and allows execution of homebrew games and apps on 5.03 Official firmware. It can allow you to play games such as Bugz!, Jellycar or run apps such as pspfiler and PSPTube. Homebrew enhances the experience of a normal PSP without any faulty side-effects.

[What it does not do?]
- Run ISO, CSO or any other form of UMD backup.
- Run PSX Games
- Touch The Flash of your beloved PSP
- Magically allow the use of Custom Firmware (on TA-088v3 or PSP 3000)
- Load plugins

How to install ChickHen on your PSP? Read this how to install ChickHen r2 on your PSP guide.

If you want to run ISO, CSO or any other form of UMD backup. You can install 5.03 Gen-A or install CFWEnabler. Both custom firmware allows you to run games from your memory stick AND run homebrew.

[via How to install Custom Firmware on your PSP]