Help Desk software

[Ted Stark]

I'm evaluating help desk software for a state library agency with both
external and internal customers.  The help desk must serve both internal
LAN users and external mulit-type library users of agency provided Web
services.  I'd like it to work on the Web and support SMTP mail so
external users can contact the desk via email as well as traditional phone
support.  The internal LAN is Windows NT.  

Is anyone on the list currently using help desk software, or, evaluated
any they thought particularly good.  I would appreciate any thoughts.

Ted Stark
State Library of Iowa
tstark at mail.lib.state.ia.us
515.281.6182