The more recent Symbian 60 Nokia phones I am talking about all do have an excellent SIP Settings client, even useful codecs, but appear to have no dialler software included. Nokia offered 'gizmo' for a while but that venture seems to have faded. If anyone knows of a good actual dialler (the Nokia equivalent of an x-lite) please advise. I am sure this could be useful to many people as 3G quality and speeds pick up.
CounterPath has a few options, X-Lite is a good free option for the pc, but you cannot connect to more than one SIP Provider. Bria is their flagship soft phone, you get it for PC/MAC, there are also Android and IPhone/IPad versions. With Bria, you can connect to multiple SIP accounts.