Apps for iOS 3.1.2 and below!!!

Hi, I have the 1st generation ipod touch with the latest installed version of iOS as 3.1.2. What i wanted to know is, is there anyway to find the apps in Itunes, that will support iOS 3.1.2. All the apps that i find in iTunes currently seems to be supporting the latest version of iOS and the latest iPhones and iPods.

Even as basic apps as Facebook does not seem to be available for iOS 3.1.2. Any pointers on how to get such apps compatible for iOS 3.1.2 would be really appreciated.

Regards,

pmbdcoe