Octro Talk is a new voip and presence application that works on Symbian Series 60 phones.
What's more interesting to me is that client Nokia has introduced the new 6300i that includes more than a SIP stack. They included a full SIP based VoIP client that is easily configurable. That means users of SIP based VoIP who are able to obtain their SIP credentials from the carrier can be totting around a VoIP phone that works over WiFi. The phone, which will retail for less than $300 doesn't have 3G capability.
A third company, Tpad has introduced a Truphone like clone that takes advantage of the stack already present in the N and E Series devices to create a full VoIP service.