climm (CLI-based Multi-Messenger) is a portable, small, yet powerful console-based ICQ and XMPP client. It supports password changing, auto-away, creation of new accounts, and other features that makes it a very complete yet simple client. It is able to send and receive messages from the ICQ network, list users that are offline and online (including their online status), search for users by email address, and look up basic (name, UIN, email) information. climm was formerly known as mICQ.
pidgin privacy please is a pidgin plugin to stop spammers from annoying you. You can block messages from certain users, block messages from people who are not on your contact list, and suppress repeated authorization requests. Optionally, senders of blocked messages can be notified with an auto-reply.