Download is also available through the Apple Dashboard Widget Directory.
This Dashboard widget displays an Apple keyboard having the selected layout. Currently, the U.S. English and Dvorak layouts are available. I created this widget as a reference to aid in learning the Dvorak layout. I was quite surprised to be unable to find any existing Dashboard widgets for this purpose.
Just download and then double-click the downloaded file, and follow the prompts. To change the layout or size of the keyboard, click the i-button in the lower right. That’s all there is to it!
Here are the full, formal instructions: Mac OS X 10.4 Tiger is required. If you’re using Safari, click the download link. When the widget download is complete, Show Dashboard, click the Plus sign to display the Widget Bar and click the widget’s icon in the Widget Bar to open it. If you’re using a browser other than Safari, click the download link. When the widget download is complete, unarchive it and place it in /Library/Widgets/ in your home folder. Show Dashboard, click the Plus sign to display the Widget Bar and click the widget’s icon in the Widget Bar to open it.
I haven’t seen any other Dashboard widgets similar to this. But there are some widgets for other environments. For example, I haven’t tried any of these out, I just wanted to mention them: Dvorak vs. Qwerty, an Opera Widget, compares the distance your fingers travel using the different layouts. Dvorak Simplified is a Yahoo! Widget for Windows.