One Instant Messenger - Version 3.2.0 One Instant Messenger is an adaptable multi protocol instant messenger client developed for Windows. The app has extremely little resource requirements being at the same time very fast. One Instant Messenger offers a wide-ranging support: AIM, ICQ, IRC, MSN and Jabber, but it also employs a plug-in system that makes possible the inclusion of other popular instant messaging protocols such as Gadu-Gadu, Netsend, Skype, Yahoo and more.