>I don't have the knowledge to answer most of your questions, but there's one thing I thought of. If your help desk people have access to the intranet, why not have them use it to get the caller's number? Then you wouldn't need another method and it's less likely for things to get out of synch.

That's a good point, Michelle. Then, it seems to me, the client's end would have to be able support either receiveing the code transparently from the web site or being able to put it in manually.