Packet Loss? How to Monitor?

I have been having 2 of our exchange users having issues with Outlook 2003, sometimes it takes a moment 30s-60s to load the calendar and sometimes hangs, both users are on wireless and I am wondering if we are getting packet loss, is this still a big issue with wireless? We are on a G network, there are about 6-7 other networks with in range of us as well. Is there anything I can do to monitor their packet loss?