Powershell is the new scripting language that will supersede VBScript and JScript. Exchange 2007 will have built-in powershell functionality, exposing *all* of its operations but as anb Exchange admin you can also use Powershell on Windows xp or 2003.
For example, you can check if your Exchange server is blacklisted on the Internet. If you have a large Exchange deployment this can be a really useful troubleshooting and monitoring tool.
For more information check out Glen Scales superb blog:
Download Powershell RC1 here: