It is no more likely to be a virus than any other attachment you may receive. File extensions do not reliably indicate the content.
Normally, a file with EML as the extension is related to Outlook Express stationery or simply saved messages created in Outlook Express.
I'd use a text editor to open it, if I was curious. You may want to ask your friend first of all why he sent it to you.
For more information on this topic, visit these other SearchSecurity resources:
Virus Prevention Tip: Fear no attachments
Virus Prevention Tip: Recognizing funny e-mails
This was first published in March 2002