Script updates of contacts in Outlook

I wanted to have all of my colleagues contact information in my iPhone so I thought of the simplest way to handle it. I quickly decided that the best way would be to simple add the appropriate domain accounts as contacts in Outlook which in a few seconds work gave me about 240 new contacts with the correct information entered as they appear in our Active Directory.

I then realised that they all had the internal speed dial phone number entered as their work number. This is a four digit number which is the same as the last four digits in the externally used number. Hence I needed a simple way to automatically add a prefix to the number for each contact, but only those that had four digits in the field since my address book is filled with external contacts as well.
After fiddling briefly with macros, csv-files and other means to get this to work, I had an epiphany and thought of PowerShell.

Three rows of PowerShell code written, tested and executed in a few minutes solved my problem

$outlook = new-object -com outlook.application
$contacts = $outlook.Session.GetDefaultFolder(10)
$contacts.Items | % { if($_.BusinessTelephoneNumber.Length -eq 4) { $_.BusinessTelephoneNumber = "123-45" + $_.BusinessTelephoneNumber; $_.save() } }

Using PowerShell to automatically update lots and lots of data will most likely be the first I think of the next time a similar task appears. This was almost ridiculously easy.