Holy god, PPCKitchen went down? I've been away FAR too long.
Are you looking for custom ROMs, or are you wanting to learn how to make one? There should be plenty of them on this forum or over at XDA. If you want to learn how to make a custom ROM, dig through the archives here and over at XDA. It's much more complicated than PPCKitchen, but it is doable.
I'd make you a ROM myself but all my Apaches are RIP.