Here's a tip to help organise your internal contacts within Outlook. Firstly you need to sign up to Linkedin if you're haven't already.
Then download the Linkedin Outlook Toolbar.
It will go through a process whereby it examines all of your emails in your inbox and then presents the contacts for you to choose who you would like to add to your Outlook address book (as well as invite to connect to you in Linkedin. Nice - all of your existing email contacts have been added!
But wait! there's more!
There's a cheeky little 'grab' tool on the toolbar. Select and highlight the signatures on any new email contacts and click 'grab' and the signature propagates itself into either updating an existing contact or creating a new contact. All the fields in the signature are inserted into the correct fields in Outlook Contacts with one simple click.