I got a G1 and have gone through the manual on setting it up. I am still having trouble with call waiting. If someone calls me when I’m on the phone, it goes directly to voice mail and does not give me the option to switch. In fact I don’t see a missed call, or hear another call coming in.
^ Didn't I tell you not to buy G1.
Anyway, check call forwarding settings, if it is set to "Forward when busy" then call waiting option won't work. Check details on page 87 & 88 of the manual.