Om Malik has caught Nokia apparently moving away from mobile VoIP a little, by reducing the native support in the latest set of N-Series devices.
Reading through various posts, my take is that the truth is a little more complex.
There are three main ways for developers/ITSPs to get VoIP software running on Symbian phones:
1) Use the native Nokia SIP stack & build your own application around it.
2) Use the native Nokia SIP stack and Nokia "Default" built-in Internet Telephony client, and build a much lighter application around these.
3) Build everything yourself, either with your own SIP stack or a proprietary mechanism.
Most wVoIP companies like Truphone have historically gone for options (1) or (2), although Fring is (I think) closer to number 3.
Lots of mobile conspiracy-theorists and bloggers are speculating that Nokia is somehow bending to the carriers' will by removing VoIP. I'm not to certain that's the main story. I think it's more likely that Nokia's decided that its default VoIP client is largely unused and fairly unloved, and in need of lots of expensive development and maintenance that isn't justified by customer demand.
Another possibility is hinted at on David Wood's (Symbian CTO) blog , which talks about competition vs. the iPhone. To me, this is a very telling comment:
"There are considerably fewer applications built into the iPhone than you can find in a standard S60 phone. That relative simplicity means that some feature-focused users will decide not to use the device. But the device taps into a new market that is arguably underserved by previous offerings. This is the very considerable market of users who don’t need every bell and whistle in feature-packed smartphones"
I'm wondering if Nokia is taking a hatchet to S60 overall, getting rid of some of the less-used features and applications that clutter its interface, in the hope of getting some more Apple-like useability. Pre-installed VoIP is certainly one thing I'd be thinking twice about in that context. If enthusiastic "featurists" want VoIP, they'll know how to get it. But for the masses, there's possibly more benefit in just getting rid of some of the confusing icons and menu items.