I'd like to invite someone from Nokia to explain how they can reasonably claim that their phones are supporting SIP.
Apart from having a number of correct sounding configuration options in the phone connection settings, no matter what you enter into these the phone is incapable of connecting to all but very few VoIP providers out there.
I have a WLAN to which both a laptop and a Nokia E65 is connected. On the laptop it took about 30 seconds to install and configure the soft-phone XLite to successfully connect and register with the VoIP provider (i.e. to an Asterisk PBX).
No matter what I do on the phone all I get is a 401 Unauthorized response, and if you ask Google on this topic you'll find TONS of other people with similar problems and very few reports of success. Even in this forum there are a lot of complaints and no-one from Nokia seems to be able to step in and provide answers or explanations.
There is no end to how mad this makes me - I bought the E65 to get a combined cell/sip phone, but in practice it's nothing more than a regular cell phone. In my book that is fraudulent and misleading, and unless something drastic happens to the (lack of) built-in SIP functionality soon I'm sending back what could otherwise have been a great phone and permanently switching to something else.