Xabber
Xabber is an open-source XMPP client for Android with multi-account support. Light and secure, with OTR support, Xabber is currently the most popular XMPP client on Google Play. When we started development of this project, usability was our number one priority. Our ambition was to create best possible chatting experience on any mobile platform while supporting many popular extensions to XMPP standard, preserving compatibility and interoperability. We believe to have succeeded in this: Xabber features an attractive, easy to use and highly customizable interface with lots of grouping options that help users arrange their chat buddies exactly as they please.
Our second priority was security. A few years ago it wasn't as important as it is today, but now it's hard to overestimate importance to chat with someone without being spied upon. Built-in OTR support allows Xabber users to escape any possible wiretapping that might come from some sinister organisations. It is also possible to use XMPP via TOR connection, wich adds another layer of security for Xabber users.

Features:
- Multiple accounts
- Quick switch between simultaneous chats
- Rich visibility settings for contacts and groups
- Compatible with all standard XMPP servers
- Pre-configured support of Gtalk, Facebook chat, Livejournal chat, Vkontakte, Ya.Online, Google Apps Gtalk account
- Multi user chat (MUC)
- Chat history
- Export history to SD card
- Emoticons
- Inline hyperlink support (web pages, YouTube, e-mail, phone numbers, XMPP Uri)
- Avatars
- View contact's information (vCard)
- Grouping contacts by groups and/or accounts
- Contact list management: add/remove/edit contacts, groups, subscriptions
- Contact search
- Integration into phone's contact list (call from the chat and chat from the phone contact list)
- Notification setting for each contact
- Full Unicode support, chat in any language
- Portrait and landscape views
- Stream compression (not all servers supported for now)
- Resources/priorities
- OTR encription
- TLS support
- Legasy SSL support
- SASL support
- Check for the server certificate
- SRV record and DNS round robin support
- Client software icons in contact list (Adium, Empathy, Gajim, Gtalk, iChat, Miranda, Pidgin, Psi, QIP, Xabber, Xabber VIP)
- Typing notification support
- Message delivery receipts
- Shortcut to a chat on home screen
List of supported (pre-configured) services:
- GTalk (Google Talk, Google Apps accounts are supported too)
- Windows Live Messenger / MSN (Android 2.2 or higher required)
- Facebook chat
- Livejournal chat
- Ya.Online
- QIP
- Odnoklassniki
Coming soon:
- Tablet interface
- Modern Android interface
- File transfer
Supported protocols:
- RFC-3920: Core
- RFC-3921: Instant Messaging and Presence
- XEP-0030: Service Discovery
- XEP-0128: Service Discovery Extensions
- XEP-0115: Entity Capabilities
- XEP-0054: vcard-temp
- XEP-0153: vCard-Based Avatars
- XEP-0045: Multi-User Chat (incompletely)
- XEP-0078: Non-SASL Authentication
- XEP-0138: Stream Compression
- XEP-0203: Delayed Delivery
- XEP-0091: Legacy Delayed Delivery
- XEP-0199: XMPP Ping
- XEP-0147: XMPP URI Scheme Query Components
- XEP-0085: Chat State Notifications
- XEP-0184: Message Delivery Receipts