What's new in R2?
Built on SQL Server 2008, SQL Server 2008 R2 delivers higher mission-critical scale, more efficient IT, and expanded reporting and analytics through self-service business intelligence. SQL Server 2008 R2 introduces two new premium editions to meet the needs of large scale datacenters and data warehouses.

Licensing
Processor License includes access for an unlimited number of users to connect from either inside the local area network (LAN) or wide area network (WAN) or outside the firewall. With a processor license, you do not need to purchase additional server licenses, CALs, or Internet Connector Licenses. This product does not come with Microsoft's maintenance program, Software Assurance (SA).