Nice and easy :)
1. Open the DNS Console
2. Expand Reverse Lookup Zones
3. Right click and select New Zone
4. Select Primary and AD Integrated (if applicable)
5. Enter the IP range (e.g. 192.168.0), leaving as many boxes blank as required to cover your IP range.
6. If applicable, enable Dynamic Updates
Optional:
7. Configure Aging to match up with the DHCP lease. e.g. 4 days No-Refresh and 4 day Refresh for an 8 day DHCP lease
HTH
Chris