You know, the OP didn't strike me as someone who was contemplating putting script like that on a box with multiple users. Or even having the authentication to do so. He certainly wasn't asking about a general program (otherwise, he would have realized that hardcoding a single username/password for a global program isn't going to work anyway).
My guess is that either 1) he has written a script which runs from this personal box noone else has access to (in which, it doesn't really matter where he stores the password), or 2) he has written a script while working on a shared box, and isn't root. In which both the script, and the config file are stored somewhere in or below his homedirectory.