The unofficial tool, Guardian Anywhere, has been developed by Future Platforms and James Hugman, who first launched it onto the Android Marketplace after entering it for the Android Developer Challenge, it was announced in a blog post.
It uses the Guardian's content API, opened up to developers in March 2009, to obtain and publish information.
The developers are not aware of any other Android applications for the Guardian: "The big win with this one is downloading all your paper overnight - so it's all sitting there on your phone when you're on the commute to work," Tom Hume from Future Platforms told Journalism.co.uk.
"Lots of other newspaper services are effectively just web browsers - you have to be online to get all the news which is really annoying when you're on the train and reception is patchy.
"We've also provided lots of ways to slice and dice the news data. The Guardian tags all its stories quite well, so it becomes easy to look up, say everything about 'executive pay' or 'Afghanistan', even across sections of the paper.
"We've also tried to retain a little bit of the Guardian look and feel throughout, though this isn't an official Guardian product."
The application also allows users to choose which sections of the paper to subscribe to; browse articles by section, author or tag; and store articles or images to a 'saved articles' folder.
In October 2008 Telegraph Media Group was the the first publisher in the UK to launch an official application for Android phones.
Google launched Android as an open-source operating system for mobile phones last year.