Adium is a popular and, probably, the best instant messaging client for you Mac.
Multiprotocol Adium instant messaging client that can connect to AIM...
An Adium IM glassy dock icon for your Mac Operating System.
Adium plugin for sharing files via Dropbox Public Link.
A Mac OS X bridge application between Adium IM and Address Book used to search, manage and keep your contacts in sync....
dotAdiumEmoticonSet Creator allows you to create your set of emoticons easily.
IronAdium is a sandboxed version of the popuplar IM client for MacOSX.