What is the difference between SaaS (software as a service) and Hosted helpdesk solution?

Nothing really. A hosted application is SaaS in its most basic form. Saas can also get into cloud hosting and a slew of other services.

Thank you Matt, btw I like your WHT username :)

Was just wondering if SaaS is good or Installing helpdesk on our server is better..

It's a matter of preference really. If you can manage your own server and application then it will probably be cheaper to host it yourself. That being said you could install the application on a cloud and still manage it yourself while having the advantages of SaaS.

Good explanation Matt :-)

Good explanation Matt :-)