Two emails sent out on every site email

Hi everyone,

Two emails are sent for every email our Drupal install makes. The messages are exactly the same, except one is delivered like half and hour later and the headers are different. Here's an example of the differences in the headers (I deleted everything that was the same and the specific data inside because I'm paranoid):

Email 1:

Received: *different IP annd SMTP ID*
Tue, 13 Apr 2010 17:00:00 -0700 (PDT)
Received: from *server*
by mx.google.com with ESMTP id *blah*;
Tue, 13 Apr 2010 17:00:00 -0700 (PDT)
Received-SPF: pass (google.com: domain of *stuff*;
Authentication-Results: mx.google.com; spf=pass (google.com: *stuff*
Date: Tue, 13 Apr 2010 17:00:00 -0700 (PDT)
Message-Id: <*some code*@mx.google.com>

X-AntiAbuse: This header was added to track abuse, please include it with any abuse report
X-AntiAbuse: Primary Hostname - *hostname*
X-AntiAbuse: Original Domain - *domain*
X-AntiAbuse: Originator/Caller UID/GID - *Blah*
X-AntiAbuse: Sender Address Domain - *address stuff*

Email 2:

Received: *different IP and SMTP ID*
Tue, 13 Apr 2010 17:35:15 -0700 (PDT)
Received-SPF: softfail (google.com: best guess record for domain of transitioning *mail server* does not designate as permitted sender)
Message-ID: <*some code*>
Received: by *IP and pop ID*
Tue, 13 Apr 2010 17:35:15 -0700 (PDT)
X-Gmail-Fetch-Info: *My gmail fetch info*
Envelope-to: *my address*
Delivery-date: Tue, 13 Apr 2010 19:00:02 -0500

X-SG-User: *our hosting server name*
X-SG-Opt: *stuff*

Strangeness, huh?