It is not on any release yet, so you’ll have the get the latest pjsip revision directly from our Subversion source code repository. Follow the guide on how to compile pjsip for BlackBerry 10.
Of course if you don’t have the BB10 Dev Alpha Device it’s not that useful, yet.
And the code is likely to change (probably a lot) while BB10 SDK matures toward production. UPDATE: It is also expected that the production release will have the all-important echo cancellation APIs.
I suppose we’ll see soon enough whether BB10 can really revive RIM and BlackBerry in the smartphone wars.
If not, well we’ve been there five years ago, when we initially supported pjsip on Symbian. And Windows CE/Windows Mobile. And so on…