Microsoft has made available considerable information about Windows Embedded Standard, (WES) which is the latest version of Windows Embedded, based on Windows XP.
There are (roughly) three versions of embedded operating systems from Microsoft:
Windows Embedded Standard: Allows a stripped down version of Windows XP for powering set-top boxes, game boxes, and machines dedicated to a single application. This is what we’re using in one version of our telemedicine set-top box.
Windows Embedded POS: An enhanced version of WES for cash registers and checkout scanner applications.
Windows Embedded CE: This is the version of Windows used for mobile phones and other hand-held and portable devices. The code base and software development tools for CE are different than Windows Embedded, with many of these related to WES.
There are a total now of twenty-nine (29!) training videos related to Windows Embedded Standard.
The Windows Embedded Developer Center site is the gateway on Microsoft’s Developer Network to all things related to Windows Embedded.
The Windows for Devices web site has information related to all version of Window Embedded as well as hardware that runs under Windows Embedded.
Smashing Magazine has a nice introduction to Ruby on Rails.