Download the Office Communications Server 2007 Resource Kit Tools from here:
http://www.microsoft.com/downloads/details.aspx?FamilyId=B9BF4F71-FB0B-4DE9-962F-C56B70A8AECD&displaylang=enOnce this is installed, browse to C:\Program Files\Microsoft Office Communications Server 2007\ResKit and run ABSConfig.exe. This is the Address Book Server Configuration Tool. You can disable phone numbers being normalized by clicking the Configure WMI tab and choosing "Apply no rules" under the Normalization Rules heading.
Also, you may want to get rid of any "Phone" attributes in the "Configure Attributes" tab if you don't need phone numbers displayed. Just change them to "None" and Apply changes.
If you want to force these new settings straight away, follow the instructions when you click OK (open command prompt, go to the directory where abserver.exe is (default = C:\Program Files\Microsoft Office Communications Server 2007\Server\Core) and run "abserver.exe -syncNow").
Hope this helps.