SQL Server 2008 R2 Pricing and Licensing

Here are some links which will help you to understand editions, pricing, and licensing of SQL Server 2008 R2.

Editions of SQL Server 2008 R2 (two new editions: Datacenter, Parallel Data Warehouse)
http://www.microsoft.com/sqlserver/2008/en/us/R2-editions.aspx

Pricing of SQL Server 2008 R2 (per processor pricing has gone up, Enterprise by 15%, Standard by 25%)
http://www.microsoft.com/sqlserver/2008/en/us/pricing.aspx

Purchasing options of SQL Server 2008 R2
http://www.microsoft.com/sqlserver/2008/en/us/how-to-buy.aspx

Edition features and comparisons of SQL Server 2008 R2
http://www.microsoft.com/sqlserver/2008/en/us/editions-compare.aspx