Developing Web Parts for SharePoint Portal Server 2003 in .NET

SharePoint allows information workers to create powerful personalized interfaces by simply dragging and dropping pre-defined Web Part Components. Web Parts are components that enable non programmers to gather information they care about and customize the appearance of Web pages. For example, one Web Part might display a user's appointment calendar; another might create a graph showing current sales figures; and a third might show a list of new business topics, each of which functions as a link to a video or audio presentation. Developers can create these Web Part components and make them available to SharePoint users, letting them build customizable pages that meet their needs. This article shows you how to build and consume a simple Web Part.

http://www.devx.com/dotnet/Article/17518