Bizzard HTML output in Email Body

I’m using MIME to attach HTML data to email bogy and using SMTP to mail it. When i cgheck the mail the HTML is displayed in bizzard format.
I have tried various characterset like ISO-88859-1, UTF-8 and encoding style for all possible combination (base64, 7bit,8 bit). But not able to get in a good lokking format. Can any one help me out in this…

Constraints are

content type = text/html; charset = UTF-8
encoding = base64