Telegram - secure, free messaging
From their FAQ:>Q: How secure is Telegram?>Very secure. We are based on a new protocol, MTProto, built by our own specialists from scratch, with security in mind. At this moment, the biggest security threat to your Telegram messages is your mother reading over your shoulder. We took care of the rest.Oh good, a bunch of randoms have rolled their own crypto.  I stopped reading at this point.