What I would like to do is to somehow associate the latitude and longitude to each item or entry, while still keeping my code valid.

Personally I don't know how people would use these coordinates. Are there programs or sites out there that would benefit from this, and if so, is there a format I should use, or a directory I should register my feeds with?

I just wanted to provide it to allowing people to use it if they could make some good use of it, but in reality, am I just wasting time?