Organizing Source Code, Regardless of Language?

og_sh0x queries: "I'm looking for a source of information dedicated to organizing source code. I see a lot of books and other resources covering syntax and various syntax-related philosophies, but I can never seem to find a good resource for organizing source code in general. For instance, at what point do you split that massive source file into multiple files? At what point do two functions approaching similar functionality need to be merged, despite the cost of digging through the source and making changes to call the new function? These are problems that plague many programming languages. Are there such resources that cover these issues?"