FreePBX 2.3.0beta2.1 & x2 Cisco 7960G

ok, i got the above and i’m trying to set this up so that i can call from ext to ext just to make sure that i can … well what do you i do ? ( hehe ) the phones i have are running sip, is there anything else that i need to do in the phones ?, i’ll go into sip config on the phones and enter in the name and the auth name and password from what i put in the ext page on freepbx, but it also has the proxy address … is that just the ip that the freepbx is serving on ?, any help would be great !!!