SQL Server 2008 Pricing and Licensing

 SQL Server 2008 is available under three licensing models:
- Server plus device client access license (CAL). Requires a license for the computer running the Microsoft server product, as well as CALs for each client device.
- Server plus user client access license (CAL). Requires a license for the computer running the Microsoft server product, as well as CALs for each user.
- Processor license. Requires a single license for each CPU in the operating system environment running SQL Server. This license includes unlimited client device access.

Following  link  (click here)  explains key licensing considerations for SQL Server 2008 customers.