How do I go about changing the icon for homebrew software?

Also, the background that is loaded when you hover the selection cursor over it.

You have to add/edit the ICON0.PNG and the PIC1.PNG in the eboot.pbp file.

http://www.puffo83.altervista.org/index2.htm
PSP BREW (spanish) You can change the language

Or
http://www.pdc.me.uk/pbp/
PSP Unpacker


They both let you open and make php's

Here ya go:
http://www.dcemu.co.uk/vbulletin/showthread.php?t=11376