Sharing Contacts w/Outlook & Express

[midplins]

We have several users with Outlook, and several use Outlook Express. (8 users total) We need an application that will enable us to share a centralized contact database without upgrading to an exchange server. I have been attempting to research an application called Dencom Global Address Book, but I can't find any reviews. Has anyone heard of or used this application? Also, if you have any suggestions as to other reputable programs, I would be quite appreciative. We need the capability to share up to 3000 contacts. Another important feature we need is the ability to search by category. I created a WAB file to share by exporting my Outlook contacts and putting a shortcut on everyone's desktop, but the only place to enter a category is the "Other" field, and we cannot sort by that field. Please help!