I can get it working fairly well with a free sip2sip.info account, but a 2Talk account refuses to connect at all. I've got the video option turned on in the 2Talk settings and the relevant codecs enabled but can't make video calls to or from the service, either to/from a "proper" videoconference system (Tandberg unit) or various Android SIP clients. Again, the sip2sip.info account works just fine though.
I can call to/from regular phone numbers okay, but no dice on SIP numbers.
Am I missing something?