Gibberbot renamed ChatSecure is a secure Instant Messenger app for Android phones, it works with any Jabber or XMPP compatible chat software (Facebook chat, GTalk, Ovi, Openfire, etc) this open source messenger developed by the Guardian Project uses end to end encryption with Off-the-Record messaging (OTR) standard, it will keep your service provider out of the equation making it impossible for an eavesdropper to read the messages.
Optionally ChatSecure can be used with Orbot (tor on Android app) to chat over the tor network, adding anonymity to an already private chat and circumventing censorship firewalls. Before signing into the chat you will be asked if you would like to save your password, you shouldn’t do this as anyone with access to your phone would be able to impersonate you.
Android secure IM ChatSecure
Off-the-Record encryption needs both parties to be using it, the people you are chatting with must have ChatSecure installed or be using a desktop computer with an instant messenger that has the plugin installed, Pidgin (Windows&Linux) and Adium (Mac) can all use Off-the-Record (OTR).
You should swap digital fingerprints first to make sure he/she is the right person behind the keyboard, ChatSecure allows you create a scannable QR (Quick Response) code out of a digital fingerprint making it easy to exchange in person, after verifying fingerprints with your partner the chatbox will be shown green indicating that encryption and identity have all been authenticated, if you can not verify your partner’s identity the chatbox will be coloured orange indicating that encryption is working but identification failed, if encryption doesn’t work because the other end hasn’t got ChatSecure installed the chatbox will be shown in red colour and can still be used.
beem android client also has OTR. (0.1.7 available in F-Droid repository)