I've published a major upgrade to the OpenNETCF MTConnect Managed SDK over on Codeplex. Earlier releases only had Agent support, but this release adds Client support. The SDK supports both the Compact Framework and the Full Framework (version 3.5 of each).
If you're wondering exactly what MTConnect is, it is a standard for how data should be published from machine tools as XML over a simple Web interface. More information on the standard can be found on the MTConnect Institute's web site, including the full specification. This SDK allows managed developers to publish and/or consume data according to the standard.