For the most part these templates are just plain ole’ fashioned HTML with a tiny bit of XML. So really the only requirements for editing or creating your own stationery is that you know a small bit of HTML. Some design skills wouldn’t hurt if you’re creating your own from scratch.

(Via The Apple Blog .)

This is a nice overview of how the new stationary works in Mail.app, but it is a tricky path to head down.

Designing HTML email that will pass through most email services and display reasonably well can be difficult.

Firing up Dreamweaver, iWeb or TextMate will get you started, but making sure the email messages sent are received and viewable can be an enormous task.

Here are a few links to chew on:

• A List Apart - CSS and Email, Kissing in a Tree
• ThinkVitamin.com - HTML Emails - Taming The Beast
• Email Labs - 20 HTML Email Tips: Ignore at Your Own Risk
• Campaign Monitor - Optimizing CSS presentation in HTML emails
• Mail Chimp - Free Email templates

My rules are as follows:

• Keep it simple
• Host all images on a server, do not embed
• Make sure your HTML degrades gracefully
• No javascript
• Don’t forget to test for mobile devices (Blackberries will choke on CSS)
• Validate - Validate - Validate

Good luck aspiring Mail Stationary designers.