Recently i was working with a JSON feed and the feed as all JSON feed was a little obfuscated. I searched for a program to provide a more readable output and found one called Tidy JSON. I downloaded it and tried it on my feed. The program worked just fine but it was not very convenient due to several reasons. The most i hated was the inconvenience i faced when traversing the DOM structure. And then it was platform dependent. In the end i decided to write my own version and since it may be useful to many people decided to publish it.
Please report any bug you find and also any feature you want me to add to it.
EDIT: Due to strange rendering bugs in IE the HTML doesn't display properly in it when the JSON input is large. Try using firefox at that time.