In one aspect, instant messaging and other forms of communications, such as push-to-talk voice...http://www.google.co.uk/patents/US8086672?utm_source=gb-gplus-sharePatent US8086672 - When-free messagingAdvanced Patent SearchPublication numberUS8086672 B2Publication typeGrantApplication numberUS 10/882,009Publication date27 Dec 2011Filing date30 Jun 2004Priority date17 Jun 2000Also published asCA25