A nice list of all new features in IIS 7.5 (the one in Windows Server 2008) is located in Michael Pietroforte post - Windows Server 2008 R2 new features - the complete list - Part 3: IIS 7.5 and Performance.
Internet Information Services 7.5 (IIS)
- PowerShell provider for IIS 7 has more than 50 new cmdlets
- Administration Pack extensions: Database Manager (SQL Server management within IIS Manager), Configuration Editor (generate scripts with a GUI to automate administrative tasks), IIS Reports, Request Filtering (HTTP filtering, URL rewriting, etc.)
- One-click publishing in Visual Studio 10
- Web Deployment Tool (formerly MS Deploy): Deployment, management, and migration of Web applications, sites, and entire servers
- Configuration Tracing: track configuration changes to IIS and applications
- New performance counters
- .NET support for Server Core
- WebDav integration (was available before as a separate extension)
- URLScan 3.0 integration: restricts the types of HTTP requests (was available before as a separate extension)
- FTP server services: integrated in the IIS administration interface; new .NET XML-based *.config format; virtual host names for FTP sites; improved logging
- Integrated extensions: new kind of extensions that appear to be an integral part of IIS
See more detailed info at the IIS team post - IIS7 in Windows Server 2008 R2.