How to determine if there are public transit apps for your region? In iOS 6, the built-in Maps application no longer provides public transportation information.  Instead, it kicks you to 3rd party apps that provide that functionality.  I'm currently running iOS 5, and won't update until I know there's a way to easily look up bus routes under iOS 6.  How can I determine if there are 3rd party transit apps that cover my region?

I'm being deliberately vague on the region I'm living in, as I want a generic answer that will be useful to public transit users in all regions.
This question is outdated as Apple Maps (iOS 10) now supports transit but an alternative to Apple Maps is Google Maps which in my experience is the best way to find transit to get from A to B but I encourage you to compare both based on where you live.