Agendus Mail is a POP/IMAP email and SMS client with support for updating mail over HotSync or live via the web. It supports a variety of folder options to keep your messages organized as well as the ability to export messages to memos.
Chatopus is a Jabber/XMPP client for instant messaging on Palm OS with support for a wide variety of chat services including Google Talk, Facebook, Twitter, MSN, Yahoo!, ICQ, QQ, and more.
InkStorm is a Bluetooth chat and whiteboard application originally included with the Tapwave Zodiac. It allows sharing messages with up to 8 connected users either through handwriting or standard text input.