How do you add an app to community sources?

Hi, I am just trying to get a grip on how all of this works, I check for updates everyday and new programs become available. but how does this work, is there a master guru out there that you submit the apps to? Or is there a place where the writers go and upload directly? Is there any testing before uploading other than the original author?

Thanks in advance if anyone knows....sometimes I feel silly downloading a program to the touch not knowing these things. I wonder if there are lots of other people who are dependent on the gui based thing with no desire to mess with ssh etc. Scott

 

Just bumping this since it did'nt get answered yet