I tried this on my “contact form submission folder” and it worked. Run through it on your machine and see how you do. For the visual learners, here is my video walk through:
In Outlook 2010 the export has moved a bit from 2007 (see below). Go to File, open, import. See the screen shot to help orient you. This export technique has the advantage you can export only the name and email address. After you export a folder run a dedupe because if people emailed you multiple times they'll show up more than once in the export file. I used technique #5 from the link below to dedupe because I have Exchange 2010. I can't believe how easy it was!
Here is how to do an export in Outlook (version 2007):
Click on 'File', 'Import and Export' to open the Wizard
Select 'Export to a File' [then click Next]
Select 'Microsoft Excel 97-2003' or a CSV file [click Next]
Select an Outlook folder [Next]
Click on Browse to select a location and then type the file name to export the information to (terminated by .xls) [Next]
Click on Map Custom Fields. This will bring up a list of all the available fields that are available in that folder.
Since we are only interested in Email address, click on Clear Map and then from the Left side click on From: (address) and drag that to the Right list
Open the output file using Excel and remove duplicates
Removing dupes. Wow this is so easy and cool! I used technique #5