Dr. Drang whipped up a neat little python script that you can place on a web server to grab weather info in mobile Safari (and Safari for that matter). I forked the project over on GitHub and styled the layout a bit. Check out the demo here. ((Be sure to add it to your homescreen so you can see the great icon I whipped up for it.))
You can’t change the location because it is hard coded, but you should be able to get it working on your web server.
Note: I am not saying this is better than My-Cast, but it is interesting what you can put together in a short period of time.