Customizing Outlook programatically

I want to modify outlook 2000 appointment form and add custom functionality to it. Can anybody guide me on how to do this

Also, I want to fetch some data from SQL server and show it in outlook calendar. I tried creating new form in vb.net and show it in place of default appointment form as suggested in

http://www.devx.com/OfficeProDev/Article/29261

but it is not working for me.

Thanks in advance,

Abhijeet.