Best way to get root password from user?

[Dennis Craven <arker rogers com>]

Hey gang,

The application I'm working on requires root privileges in order to
perform a few of the functions I'd like it to. I'd like to just pop up a
simple dialog and have the user enter the root password when required. I
would like to be able to check the validity of the password prior to
running the functions that require it and having them fail.

Obviously, I'd also like to keep the process fairly secure if possible. 

If anyone has some keywords for me to search on or some examples to get
me started I'd very much appreciate it.

Thanks,
Dennis Craven

P.S.: My app already requires Gnome in order to work, so if anyone knows
of any helpful functions in the Gnome API, then that would be fine too.