I work for an IT support company, and we use microsoft crm 3.0
it runs in the browser, and can be accessable from anywhere (we haven't currently got this set up, and use a terminal server when onsite).
I should note we are a microsoft partner.
There are some annoying quirks with the sysem.
First and foremost being that since it runs from the browser, it will never seem as fast as a true desktop application.
Secondly, it can be customized to your situation. this is a blessing and curse. It isn't an out-of-the-box type application. Youwill need a web developer to set it up.
however it can be tailor-made to your needs.
Running from a server, means centralised backups, and no loss of data due to a client pc..
Personally the slowness drives me crazy, and i find myself logging cases in keynote, and then filling in the crm cases later when i get a chance.
I'm thinking of switching to mylifesorganised due to it's outlook integration. We get a lot of support calls through email.
i believe sharepoint 2007 should improve this product a great deal though, in speed, features, and most importanly intuitiveness.
We are also an altiris partner (
www.altiris.com) and are looking at their helpdesk system, which seems similar.
This maybe too complex for your needs, but if anyone wants some info, drop me a line.