I'm looking for an alternative to Package Foundry. It doesn't have to be - and I'm sure won't be - free or anything like that.
It also needs to be able to create a configuration file, which asks for their database details and such. Without that, it's just an automated FTP app, which is of limited use.
Are there any alternatives which might be able to automate the uploading and then just request some info from the user, and then perform a check to make sure they're valid?
Take a look at InstallJammer. It's a free, open source installer that can do everything you need. Drop by the forums if you need some help getting started with your installer, and I'll be glad to show you how to do what you want here. It's actually been done by many before, so it's not all that hard. :)
NSIS (Nullsoft Scriptable Install System) is a professional open source system to create Windows installers. It is designed to be as small and flexible as possible and is therefore very suitable for internet distribution.
Or distribute your application via a PEAR channel.