Here is a must read article by David Greiner for everyone involved in designing, creating or specifying e-mail newsletters and e-mail marketing campaign.

Key points:

• Make sure your HTML e-mail looks good and is readable to peaple with images turned off
• Test in a variety of e-mail clients
• CSS is OK, but use with caution, and don’t use for position — and be sure to embed your CSS

There’s no point in sending out HTML e-mail if you’re not going to do it right. As they say, read the whole thing