I though I’d gather in one place all the useful links I found with information on development of Windows Sidebar gadgets.
- Gadget Development Overview whitepaper should be you first stop. It’s a short article explaining the basics of gadget development.
- Windows Sidebar Reference is the only documentation that is currently available. It’s not very detailed, neither always accurate but it should still serve you well.
- Gadget Corner is a blog maintained by the Windows Sidebar team. It contains a few articles with information that can’t be found anywhere else.
- Sidebar Gadgets Forum is the only forum dedicated to gadget development. On top of that the Windows Sidebar team members have the habit of answering the posted questions.
Last but not least, don't underestimate the gadgets that come with Windows Vista. Since it’s all HTML, CSS and JavaScript, all the source code is available and can be a good learning material when trying to determine how some functionality has been achieved. You can find them in C:\Program Files\Windows Sidebar\Gadgets directory.