Microsoft has updated the evaluation version of Windows Server 2008 R2

Windows Server 2008 R2 builds on the award-winning foundation of Windows Server 2008, expanding existing technology and adding new features to enable organizations to increase the reliability and flexibility of their server infrastructures.

This software is for evaluation and testing purposes. The evaluation is available in ISO format. Web, Standard, Enterprise and Datacenter editions are available via the same download. You will be prompted for edition installation at setup. Evaluating any version of Windows Server 2008 R2 software does not require entering a product key, however will require activation within 10 days. Failing to activate the evaluation will cause the licensing service to shut the machine down every hour (The 10 day activation period can be reset five (5) times by using the rearm command. See below for further information on activation rearm). Once activated, the evaluation will run for 180 days. After this time, you will need to uninstall the evaluation software and reinstall a fully-licensed version of Windows Server 2008 R2.

  Windows Server 2008 R2 Evaluation (Updated)