I want to create a custom Addon/plugin for Outlook 2003, to support integrated functionality with a task management system.
I am unable to find many good development resources for the same.
Can someone please explain Outlook 2003 architecure and development of a plugin.
Good links/resources are also welcome.
Here is a tutorial on outlook architecture getting started building Outlook 2003 plugins from MSDN: http://msdn.microsoft.com/en-us/library/aa289167.aspx
There is also a huge list of resources here: http://www.microeye.com/resources/res_tech_vsnet.htm
Good luck!
What you want can be done.
The bottom line is that you need to use Visual Studio 2005 or Visual Studio 2008 plus Visual Studio Tools for Office (VSTO) plus Outlook 2003 (of course) to build an "Adddin" for Outlook.
Addins are quite complicated to write mostly because Outlook has eccentricities that are not well documented. For example, a method Outlook.MailItem.GetHashCode() is not always the same even for the same object despite what you might expect from something as seemingly absolute as a 'HashCode' for an object. Knowing that and many other quirks of the VSTO+Outlook API are for what the professionals get paid. There are MANY quirks. If you are learning then you will need to start with the resources Gdeglin has provided.
Also look at the MSDN VSTO forum: http://social.msdn.microsoft.com/Forums/en-US/vsto/threads <- very active!
And Outlook code: http://www.outlookcode.com/
Also here is a Google search on MSDN for various VSTO 'tips': http://bit.ly/105ZDR