IM Gateway plugin allows you to access AIM and ICQ messenger accounts directly from the chat room. Unlike traditional desktop messengers this plugin doesn't require additional software installation on user's side. The main prerequisite needed to run the plugin is Open Fire jabber server, more information can be found at official website - www.igniterealtime.org. Onsite description.
After server installation plugin's connection settings to be configured in the following file: flashcoms\common\settings\ imGateway.xml