Setting application to be the default application

FROM : Ryan Homer
DATE : Tue Jan 08 20:12:33 2008

Maybe someone can lead me in the right direction as I am not sure 
exactly what to look for in the docs.

I know that based on an application's plist, you can associate your 
app with a file extension, so that your app will open .txt files 
instead of Text Edit. However, there are also other ways to establish 
these associations, such as clicking on a hyperlink starting with 
http:// should open that link in the default browser and one that 
starts with ftp:// should use the default FTP application.

I have the "Default Apps" panel installed in my System Preferences and 
in the Apps section, my application does not even show up in there. 
There is also association by MIME Type, URLs, UTIs...

How would I associate links like http: and ftp: with my application?
What is the link that is associated with Instant Messaging 
applications? I ask this because in "Default Apps" there is the URLs 
section and there's an aim link that's associated with iChat, for 
example as well as iChat's own "ichat" URL. Would these be something 
like "ichat://username" or "aim://screenname"?
What is a UTI?
Where in the Cocoa documentation can I find info on this?

Thanks!