I read somewhere that when creating a HTML email, you should use the table-based layout. You should not care about creating tableless css based layout. Is that true? I have
If you want your HTML-email to look good in most email clients, you should write your HTML as it still was 1999 :)
I won't advise you to do it, but you had probably hear this because a lot of email reader supports only a few html and css. They often don't bundle a full html/css parser, and in the past table was much used to do layouts..
+1 on Campaign Monitor's advice. I've also seen a lot of great content from Emma. In my experience, the simpler you can make an email newsletter template, the better. This is doubly-true in a world where an increasing percentage of users are reading your message on a mobile device with a small screen.
I'd highly recommend paying a visit to the Email Standards Project website. It lists almost every major email client (both standalone and web-based) on the market and outlines how much HTML support is built into each one.
Also check out Campaign Monitor's email design guidelines for some practical guides for proper HTML email building -- including, sadly yes, "use tables."
In the past it was common to use tables for page layout, and many people who create pages are still more comfortable doing it this way.
As James says, best practice is to use CSS positioning facilities for page layout except when it actually is tabular data; but personally I often find it hard to get the effects I want with CSS.
You may want to look at this, although this is specifically about the Oulook html/css subset support described:
http://msdn.microsoft.com/en-us/library/aa338201.aspx