Here are sites of interest:
Palm Programmers Group: a lot of interesting articles if you want to develop
documentation: PilRC is certainly the best way to integrate resources in
your palm apps, even using CodeWarrior.
Sony Clie web site : PEG-N760C, PEG-T615C, PEG-T415, PEG-S360. Prices, OS updates, Infos...
Sony Clie Developer : all what you need to exploit Clie' specificities. Emulator, rom, SDK.
Palm-Recherche : a lot of sites referenced talking about Palm OS computers. Palm-recherche is a french site, but PalmOS sites referenced are all around the world (english, french, deutsh, japanese, spanish...).