How do I configure custom URL handlers on OS X?

I get that you can tell the system that a particular program is able to handle a certain scheme / protocol with the Info.plist file:

CFBundleURLTypes  CFBundleURLName Local File CFBundleURLSchemes local    NSUIElement 

But if there are multiple applications that are capable of opening the same URL handler, such as mailto: how do you specify which one you want the system to use?

There were some references to utilities like the More Internet preference pane which no longer seems to be available from the author's site. I did find it online by Googling but it seems a bit shaky - like it was written for an older OSX - perhaps Tiger.

I haven't been able to find information on how to set the URL handler for protocols and custom protocols. I'm assuming there is a plist file somewhere that I can edit - or maybe there is a newer, better utility that works well with Mountain Lion?