As announced by Moshe Kigler in the ICQ Beta Testers facebook group, ICQ 7.6 final and ICQ on-site beta has been released.
So, now ICQ can connect you to 4 different IM accounts at once:
Despite being mentioned as not working in the Known Issues list, ICQ for Mac and ICQ for Linux can handle GTalk contacts as well. You cannot add them from within the client but if you have added them using ICQ for Windows or ICQ for iPhone, then they will display as available if they are online and you can chat with them.
ICQ on-site beta however is a widget you can put into your blog or website to provide visitors an abillity to chat.
Interesting is: For the first time the ICQ Team even provides a direct way of support incase you have any problem with the widget!
Last but not least they also released ICQ for iPhone 2.8 to add GTalk functionality. Android will be coming later!