Keyring Installed on my Palm gives me access to all my passwords where ever I am. I also have it sync'd to my desktop and accessible via a desktop client, so should I ever lose or have the PDA stolen, I can go through and change all my passwords quickly, plus if the PDA dies, I still have access to all the passwords.
keepass and password safe are both good alternatives. But I like to have my passwords with me at all times. It encourages use of much more random, longer and stronger passwords that way.
Also, it means I never have to enter the master password on my PC (unless I lose the PDA) so should a trojan find it's way onto my machine, the best they can do is steal the encrypted password database and log any passwords I may type into my PC.