This may be incredibly obvious to everyone else but I have wanted to do a better job of managing my contacts on my iPhone. When I used Windows Mobile, I could put categories on my contacts in Outlook and those categories meant something on the phone as well. The iPhone doesn’t support categories so all my contacts (approaching 1000 at this writing) were in one big list.
I did a little experiment and found out that the Groups function on your iPhone includes not only your Global Address Book from your company, but also any sub-folders of your Contacts on the Exchange server. This way you can divide different types of contacts (work, customers, family, vendors, etc. into different Contact folders on your server and they appear correctly on your phone.
Here is a screen shot of my folders in Exchange:
and here is a screen shot of the Groups on my iPhone.
To make the sub-folders available to you when you are addressing email or looking for contact details, in Outlook go to Tools|Address Book and then do Tools|Options in the Address Book. This will let you change your search preferences on the different Contact folders that you have available (including your Global Address Book from your Exchange server).
Hope this helps! I solved one of my problems.
I am done with this topic for now but I reserve the right to rant more on it someday.