There are ways to trace, but you are going to run into walls because you don't have the rights to. At the very least, read the email headers. It's by far the best you can find out.
http://www.sgforums.com/?action=post_display&post_id=5936272Ignore the phishing parts.
Once you set to see headers, you will see this:
X-Apparently-To:
[email protected] via IP Address; Thu, 21 Jun 2007 20:28:05 -0700
X-Originating-IP: [IP Address]
Return-Path:
Authentication-Results: mta469.mail.mud.yahoo.com from=yahoo.com; domainkeys=pass (ok)

optional.
Not all email headers will show this. Yahoo! mail shows this, so you can verify if that person's ID is real.Received: from 69.147.97.76 (HELO
) (IP Address) by mta469.mail.mud.yahoo.com with SMTP; Thu, 21 Jun 2007 20:28:05 -0700
Received: (qmail 71593 invoked by uid 60001); 22 Jun 2007 03:28:04 -0000
DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=X-YMail-OSG:Received:
Date:From:Subject:To:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-ID; b=GsHDKhs2linryk9OIUKGFx/lO4E4YEBkqZS5D5qK+R/CR7WnYrA9VdaWnQikvRm0TH7nIOgUFmVcS3NHeX00KdPk802Uumv5z1DV9uoWtUWiBc0jOINvLCetsYWBvh+EA7BPUyl2kgrrxAbckKiT41ZiKcUAvxSzd+M2e4TmLpo=;
X-YMail-OSG: t7EelRQVM1kqcPE45wRxVmipvVzuQF7eFElT_710DpLCT3kEeHYtb8wWJyzofDwyiBhg.q.dJ7jBwod1Lx4KPYJVteUzn3yIvRaLqsyu2YvoHPVba5rpAMH8xh2tqqcBbFEJOZUnmzJ0ZseTCY38
Received: from [IP Address] by web63606.mail.re1.yahoo.com via HTTP; Thu, 21 Jun 2007 20:28:04 PDT
Date: Thu, 21 Jun 2007 20:28:04 -0700 (PDT)
From: "mayi"
Yahoo! DomainKeys has confirmed that this message was sent by yahoo.com. Learn more
Subject: RE: whatever
To:
[email protected]MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Transfer-Encoding: 8bit
Message-ID:
Content-Length: 483
Google the IP address. You will be able to find his ISP. If you receive lots of spams from the same IP address, the ISP will inform him.