This is when you need to send 'HTML page you want to send as body of the message' without css and javascript
Create a new message and just add eg [URL:http://www.yahoo.com]
Now as the message sends css and javascript some email clients ie gmail will not format the email.
Sending a message without css and javascript
Create rss feeds of your content
Run your rss feed through the http://www.rss2html.com script (which you uploaded to your server) so that you will now have a php include code
Create for example mynewsletter.php and add your php include code from above and voila! you have a clean page which you can theme as you wish
Use inline css (not an attached file) which you can see at http://inlinestyler.torchboxapps.com
Now if you use scheduling you can automate your newsletter that sends daily, weekly etc
http://www.filmcontact.com