Yet another of my applications for mobile phones is JSRSupport, a really simple application that I just wrote. It's intended for mobile phone developers, and displays which mobile phone related JSRs a phone supports.
You can download JSRSupport by visiting http://trivergia.com/jsrsupport/js.jad in your mobile phone's browser. JSRSupport is about 2KB in size, so keep in mind that you'll probably get charged by your wireless carrier for downloading stuff. Other than that, JSRSupport is free.