Trying out the property system
You can, of course, wait for Windows Vista to ship before checking out the property system. But if you are curious or bored, here are a few other things you might do:
Download the Windows Vista Platform SDK:
The most recent Platform SDK. The SDK contains all the headers and libraries you need to start building apps that make use of the property system APIs. The SDK is updated pretty often, so just look for the version matching the copy of Vista you have for testing.
Download (or order) Windows Vista RC1:
Windows Vista RC1 will be available or download or ordering via the Customer Preview Program. I don't know when it will come out, or the details about downloading, but I think you will hear about this release from various websites.
Download Windows Desktop Search 3.0 (for Windows XP/2003):
The property system APIs will actually ship in Windows Desktop Search 3.0. This product is currently in Beta 2 if you would like to give it a shot. My only caveat is that the support for extracting properties from files will not be as complete as it will be in Vista. But you can still check out the APIs, use the support that is there, etc.
On a more sober note, if you build a project using the Vista PSDK and plan to run the apps on XP, be sure to ask for the Windows XP/2003 subsystem and header macros. If not, your app will assume all those nifty Vista APIs are on your system. Unfortunately, I don't know how to do this myself yet, but if I figure this out, I'll mention it here.
[2006/09/07 - BK: I've been told this is a stable link to current and future Windows Vista Beta downloads, including its SDKs and RC1 content: http://msdn.microsoft.com/windowsvista/downloads/products/getthebeta/]