NetTalk Portable IRC Client
NetTalk is a Portable Internet Relay Chat IRC App. Net Talk utilizes a Windows style interface, making is easy to use. It supports English, Spanish, Dutch, Russian, Chinese, Hungarian and German languages.
Free IRC Chat
X-xChat - Free Portable IRC Chat Client
X-xChat is another great Free Portable IRC Chat Client offered by winPenPack. X-xChat is essentially based on the unofficial XChat with a portable wrapper. Aside from being portable, it offers two additional features not found in most other IRC Chat Clients; colored nicknames and alignment by text as opposed to alignment by nicks. These features are carried down by the original X-Chat.
0irc - Tiny Portable Internet Relay Chat (IRC)
0irc is the smallest known (IRC) Internet Relay Chat client in the world for Windows. Not only does it have a small footprint, but also contains a small set of necessary features. Features such as chat, dcc file transfers, multiple server connections and an all channel overview. 0irc is command line based with no menu, so it is meant for those who already know their way around IRC Clients. 0irc requires only 172KB for complete installation.
HydraIRC - Portable IRC Chat App
HydraIRC; A Portable Internet Relay Chat (IRC) App. This dockable IRC client supports both DCC chat and file transfers. The author also offers a plugin that includes a bonus sound pack with sound notifications for those who prefer audible notifications. This Portable IRC Client requires 2.17 MB of disk space once extracted.