After trying (and finally succeeding on my end) in getting ekiga to work as far as a succesfull connection to the echo server (sip:firstname.lastname@example.org), I now understand why people are angry about pulse and other sound.
I have a bog common HDA intel audio. Q965 chipset. I had to go in to gst-mixer and enable the Microphone (it wanted to enable the Front microphone which I don't use 'cause it has a 60hz hum). Then I had to enable two recording device (Capture and Capture 1). I had to unmute the microphone on Capture which let pulse hear the mike. Then I had to unmute mike on Capture 1 which let non-pulse Alsa hear the mike. I had to disable the Mixer because otherwise the mike was linked to the speakers and instant echo ensued.
I also had to bump Fedora 11 to the 2.6.30 kernel in testing.
Finally everything was working. Then I couldn't get the distant end to be able to connect to ekiga.net from behind their NAT. And I've been working on and with linux since 1994 everyday since 1994 (I even have a freerunner as my daily phone).
I decided to try empathy instead. Not even close to being close to connecting. Tried gossip. Good luck! Linphone? Not a hope.
First time I've come close to crying since I had a double disk failure on my raid 5 last year. (which I fully recovered from with no data loss by the way thanks to Neil Brown and the others on the raid list).