Within the CRM system you can schedule duplicate detection rules to run on a scheduled basis and send you (and other users) a link to the results when it is completed. The template for the email that is sent is found by going to Settings, Business Management, E-mail Templates and then scrolling down to the Duplicate Detection Task Completion Template.
If you open up the template you will then see the following email message format. We recently discovered an issue during an upgrade from CRM 4 to CRM 2011. As shown in the message below the url for the report is at http://domain:5555 etc. This is actually the url to the CRM 4 system which is no longer valid. So during the upgrade process it appears that this link is not automatically updated. Once we updated the url in the message to https://orgname.domain.com:444 etc the client was able to navigate directly to the completed report.