For all you Windows/.NET aficionados out there: we have just released the final 3.0 version of the eBay SDK for Windows. I blogged about the beta release a few months ago. Using this SDK is the easiest way to get started coding eBay apps using .NET languages like C# and VB.NET. The most significant thing about this version is that it is based on the eBay SOAP API. It also picks up the most recent calls that have been added to the API, such as my favorite, the AddToWatchList call.
If you are using the 2.6 version of the SDK for Windows or earlier, you should migrate to this version of the SDK (or pick up the SOAP API or New XML API instead) well in advance of June 1, 2006, which is the date the old version of the SDK for Windows and the Legacy XML API on which it is based will no longer function.