iTalk Messenger Lite - iTalk Messenger is an instant messenger that allows Peer2Peer communications between iOS devices. As long as you are connected to a router or access point with WiFi enabled, you will be able to chat with buddies who are connected to the same access point.
Besides WiFi, the app allows you to chat via Bluetooth
BeejiveIM for Facebook Chat (iPhone) - BeejiveIM is a reliable and user-friendly mobile IM application for your mobile device, featuring desktop-like instant messaging and always-on efficient networking.
BeejiveIM for Facebook Chat lets you chat on Facebook's chat network anytime, anywhere with the proven reliability of BeejiveIM
Everyday With You - Everyday With You is an iPhone app that allows you to chat with cute bot girls anytime you want. All of the girls have different personalities and message types. Some of the girls are sensitive, while others like to flirt.
The girls will send you thousands of unique scripted messages that will grow more personal over time
Tchatche for iPhone/iPad - Each day, more than 15 million private messages are exchanged on Tchatche.
Each day, up to 30,000 users are simultaneous connected
InstaTalks - InstaTalks is the easiest and fastest way to chat with all your Instagram friends. It lets exchange private messages with other users on Instagram and share private photos with them. In addition, thanks to an innovative search system, you can discover other InstaTalks users near you, and start chatting with them. No registration required
TalkRoom for GTalk - TalkRoom for GTalk is a user-friendly instant messenger for iPhone and iPod touch. It allows you to keep in touch with all your friends on Google Talk while on the go
TalkRoom for Facebook Chat HD - TalkRoom for Facebook Chat is a user-friendly instant messenger for iPad. It allows you to keep in touch with all your friends on Facebook while on the go
TalkRoom for GTalk HD - TalkRoom for GTalk is a user-friendly instant messenger for iPad. It allows you to keep in touch with all your friends on Google Talk while on the go
TalkRoom for AIM - TalkRoom for AIM is a user-friendly instant messenger for iPhone, iPod touch, and iPad. It allows you to keep in touch with all your friends on AIM while on the go
TalkRoom for MSN - TalkRoom for MSN is a user-friendly instant messenger for iPhone, iPod touch, and iPad. It allows you to keep in touch with all your friends on MSN (Windows Live) while on the go