14 tips for HTML Email newsletter design
When creating HTML Email newsletters, designers should keep in mind that there are a lot of similarities, but even more differences between displaying content on a web page in a browser and effectively showing content in an e-mail client. Many common techniques of web page design simply do not work in e-mail.
Cameron Chapman of Sixrevisions.com wrote a very useful blog post about this subject, with many examples, best practices and recommendations: Creating HTML Emails: An Overview for Web Designers.

