These are the settings i use for teamspeak with a sblive
open alsamixer, and make sure you have:
"Mic" in 0% Volume (zero), and "Capture" writen over it (use space to toggle the capture flag).
Mic Boost muted (MM over it, use "m" to toggle)
"Capture" at 80% Volume, and capture flag set (capture writen over it)
"AC97 Capture" at 100%
Nothing else (except "Mic" and "Caputure" to have the Capture flag set).
Then try with push to talk, and see if somebody can hear you (or if you can hear yourself in the local testmode).
Good luck.