no need to create a subsim app there is an app called tapatalk that can work with many forums:
http://www.tapatalk.com/
It works with all the popular smartphones, iphone, android, blackberry, win7 and webos. I use the iphone version and it works brilliantly.
Now Neal, you might want to make an app if you want to make the rest of the site available in mobile format but better think about it-no one will be downloading stuff onto their cell phone.