From the Beta labs blog post:
Many thanks to everyone that tested the Counters application during its beta trial! Thanks to your help and feedback we have published it globally on the Marketplace (open this link on your phone or scan the QR code below) and, moreover, we know what are the most important features our customers need. We will implement new features, make bug fixes, and bring them to the market as soon as we can.
Once the application starts to gather data, tapping on the three different allowances will give you a breakdown not just of the monthly usage, but the all time usage, and the people you most frequently contact.
It's a nice little utility, and some of us here at AAWP have been using it over the beta period. It's unlikely to stay as a Marketplace only download, I'd expect it to be included in the firmware of new retail devices, and the inclusion of something similar to Contacts as part of Nokia's Windows Phone 8 must be on the cards.
For the moment, you can download Counters from the Marketplace, or via the AAWP App Directory.