.NET Compact Framework
Last night's presentation by Dan Sellers at the Winnipeg .NET User Group meeting on Compact Device development reminded me that I hadn't blogged about the OpenNETCF.Org library of open source stuff for compact device development.
Besides being a valuable website itself, the OpenNETCF.Org library of framework code fills in the gaps in the .NET Compact Framework quite nicely. Things like more XML and serialization support, cryptography, and some custom controls for accessing the features of a PocketPC, such as the voice recorder or capturing the special buttons. It even has WSE 2.0 support. Plus it integrates into Visual Studio.NET 2003 and includes context Help.
I wouldn't do CF development without it. At least on the current platform.