Earlier this week the Android development team released some news about Android v2.3, aka Gingerbread. This has a lot of people more than a bit excited as one of the new features is a built-in SIP stack.
Some point to this as being a major step toward the integration of Google Voice and Android devices. With a SIP stack included in the OS it will be much easier for people to develop soft phones that leverage the hardware and the data side of Android handsets.
The built-in SIP stack will work with any SIP service provider, giving users tremendous flexibility in choosing who gets their business. It also means that close integration with an IP-PBX will be easier than ever before.