Logorrhea is your one-stop solution for iChat log browsing and searching. iChat can be configured to log all messages sent and received, which is all fine and good - until you need to actually find a specific conversation that is. Enter Logorrhea. It features fast browsing of logs by buddy and date and keyword searching of logs.
AIMSpy is an application that parses and displays content from instant messaging systems using the local network. It is multi-threaded, uses BPF devices for network access, and includes fairly thorough support for the AIM chat protocol and rudimentary support for the Rendezvous (iChat) protocol.
GNUSTEP Live CD contains a lot of software for GNUstep, a free implementation of the OPENSTEP framework (which is also directly used in Mac OS X as Cocoa). It includes excellent applications for RAD (GORM and ProjectCenter). The CD is available for i486, AMD64, Apple Mac PowerPC, and Sun UltraSPARC computers.
TalkSoup is a fully configurable graphical IRC client for both GNUstep and Mac OS X. Its simplistic interface is made extremely powerful by the fact that all parts of the IRC client are implemented as runtime-loaded plugins, so additional plugins can be made to further extend TalkSoup. TalkSoup supports a tabbed interface, DCC file transfer, and most common features found in other IRC clients.