How to attach an excel file/ dat file thru unix mails

Hi.

I want to attach a .xls or .dat file while sending mail thru unix.

I have come across diff attachments sending options, but allthose embeds the content in the mail. I want the attachement to be send as such.

Please help me out.

regards
Diwakar

I've always done:

uuencode myfile myfile.mail | mail -s "myfile" address@domain.com