Ok all, I answered my own question today. Here is a quick how-to.
Install OpenSSH on your iPhone.
SSH into your iPhone using your favorite FTP client.
Navigate to "/var/mobile/Library/Installer"
In that folder there will be multiple .plist files, download "PackageSources.plist"
::The following step is much easier on a Mac, since there are programs made to do this, I am not sure if there are programs made for PCs too.::
Open the .plist file and add in the new sources you want to add.
Send the file back to your iPhone.
Open Installer.app
Refresh your sources, and you they are good to go!