A little correction after testing this with IE4.01 SP1 using Outlook Express as my default email client and default MAPI client. The subject needs to be prefaced with a ? not an &. So this argument should work in ShellExecute:

"mailto:x@y?subject=test subject&body=this is the body of the message%0d%0aI sure hope that it works&cc=cc@cc.com&bcc=bcc@bcc.com"

If the email client doesn't support the clauses it might either ignore them or tack the clause onto the prior clause in the stream.

>Mark,
>
>A little update based on a mail I just got from MS. Check this KB article http://support.microsoft.com/support/kb/articles/q188/0/19.asp IE4 now supports several additional clauses on a mailto: target tag.