How to develop addin for MS Outlook?

How do I develop addin for MS Outlook that works with all 1. Outlook 2010 2. Outlook 2007 3. Outlook 2003

I have developed addin that works well with 2010 and 2007 BUT NOT with 2003.

I want something like this that works well with all the above three :)

You need VSTO (Visual Studio Tools for Office). Here is an article to get you started.

You can also check out Office Development Center.

You need to go for NetOffice. It will allow you to abstract out from Outlook version. Also it has a powerful diagnostic tool that will tell you which version of outlook your add-in is compatible with based on API features you use in your code.

Worked nicely for me.

http://netoffice.codeplex.com/