International Characters from a US Keyboard?

[David Wright <ichbin@shadlen.org>]

I run the Gnome session manager on a Debian sid machine attached to a US
keyboard. When I am writing in English, which is most of the time,
that's fine. But I also often write in German and occasionally in
French. Is there a way to produce the standard accented characters (at
least in Gnome applications) using keyboard combinations?

I'm very tired of mousing up to the little gnome character pallet
utility every few words when write a multi-page document. I'd like to be
able to do something like ALT-" + O to produce an umlauted O.

By the way, Windows has had this feature nailed down pat for about the
last decade. Same key combinations, doesn't depend on the window
manager, session manager, or application. Amazing. :-)