Now some of my html messages come as an attachement with an .txt extension, if I save that file and rename it .html I can read it fine.  It says that the character set not supported.

I am using Exchange 5.5 sp3 and spamfilter as the smtp gateway.

Does anyone had a message that looks like this one. 

This message uses a character set that is not supported by the Internet
Service.  To view the original message content,  open the attached message.
If the text doesn't display correctly, save the attachment to disk, and then
open it using a viewer that can display the original character set.