@ zapman
I'm using a Nokia-brand headset (as anything made for iphone will NOT work, as mentioned by Alerino on these boards), in the ALSA configuration, I have my right input turned on to Sub Mic (for the external mic port)... I have not done any port opening for my network manually (never looked to see if anything changed automatically, but I'm pretty sure it hasn't and I'm using the default network port settings). Are you using any sort of external mic or speakers are all internal components? I have never attempted to use the internal mic for this purpose.
I have not made outgoing calls with my setup from within linphone (I have the backend of my whole setup configured it with google voice, so my outgoing calls are dialed from another location and are seen as incoming on Linphone). I am able to hear the other end (local automated system I dialed to test with) but I have not gotten a chance to officially test the mic yet... had been playing with installing pulseaudio and tweaking the settings for that for the last week or so and have technically had no sound for a while (running on SD, not NAND). Just recently dropped a fresh install on another SD card (as in about an hour ago) so once I import the appdata with my configuration (I always backup my appdata when I get a working configuration on ANY pnd so I don't have to reinvent the wheel... much) I will make some actual calls to see if I get audio both ways and let you know.
Since the conversation between you and I are based on Linphone and not Ekiga, I'd like to continue this discussion over on the Linphone thread... also, join the Linphone mailing list, as I'm pretty sure I have seen sipgate mentioned in the mailing list over the last month or two... I installed Linphone on my laptop and desktop before I even got my Pandora because that was the only VOIP solution that seemed to be functional at all (so far) on Pandora, so I prepared myself on my standard systems (also, I have uniformity for my VOIP solution between all 3 systems).