With the Google Deskbar API, you can write plug-ins to add your own features to the Google Deskbar. Plug-ins can be written in any .NET language, such as C# or Visual Basic.NET.
Google has released Google Deskbar API. With this API, Google Deskbar will pass search term to your plugin code, which then can return a specific URL to be displayed in your browser or Deskbar mini-browser. It seems that it even allows you to run other programs from your plugin code.
Note that your plugin should be written in one of .NET languages like C# or VB.NET and should be installed as a .NET Assembly DLL to Deskbar Plugin directory. If you want to use Perl as a .NET language, you'd better try Perl Dev Kit from ActivePerl.
The document says it would be interesting to:
- Locate and play a music play list on your hard drive
- Solve algebraic equations
- Send instant messages from the Deskbar
There's also an API discussion group.
Without this API, Google Deskbar still allows you to customize Search URL in "Options", but this API gives your more flexibility to use Google Deskbar as a front-end to everything you want to search from your Desktop.