Looking for 1.5.7+ files

[TankNSpank]

Title is self explanatory. I'm an aspiring server developer trying to get my hands on files 1.5.7 or higher from a reliable source. Looking to speak with experienced developers and learn as much as possible.

EDIT:
I supposed I posted this in the wrong section. I don't know how to delete the thread, so I'll leave it here to see the responses instead of making an entirely new post.