Windows Server 2008 includes two technologies designed to increase server availability and scalability: failover clusters and Network Load Balancing (NLB). Failover clusters primarily provide high availability. Network Load Balancing provides scalability and helps increase the availability of Web-based services.
Failover Clustering in the Windows Server 2008 Technical Library
Evaluation
Getting Started
Planning and Architecture
Deployment, Operations, and Troubleshooting
Network Load Balancing in the Windows Server 2008 Technical Library
Getting Started
Deployment, Operations, and Troubleshooting