Atlassian will provide support for gadgets that are part of supported plugins. Please refer to Atlassian supported plugins. Atlassian support does not cover gadgets on external sites like iGoogle or Gmail. See the detailed section on gadget limitations.
Here are sample gadgets you can use to learn more about how to develop your own gadgets:
The basic version is designed to run standalone. It fetches anonymously-viewable issues from jira.atlassian.com. You can use the XML spec file URL directly to serve the gadget, or check it out and copy the containing directory to your own web server.
The plugin version can be checked out and built with Maven 2 (by running mvn package). You can install the resulting JAR file into JIRA 4.0 or later.
Tree Frog -- This is the gadget URL that you can add directly to your dashboard. As an externally developed gadget, we cannot guarantee that this gadget works or will continue to work. But it nevertheless may provide a good starting point for your own experimentation.
In addition, if you have access to the JIRA source code (which you should if you have a commercial license), you can find additional examples of Gadgets by looking at those included with JIRA. You can find which gadgets JIRA includes by checking the descriptor in the JIRA source code at: