I'm running both Ubuntu (10.04) and WinXp on the same machine, thus using the same keyboard. On Windows I have selected "United States (International)" as my keyboard setting.
In Ubuntu I have "USA International (AltGr Dead Keys)". However, they work slightly different.
When I press the ["] -key (or the [']-key) in Windows, the resulting character depends on the next typed character. For example I can get foreign characters like "é" and "ë".
When I press the ["] -key in Ubuntu, it just displays a " character, thus not allowing me to get special characters.
I prefer the Windows version, but don't know how to get this done in Ubuntu.
Here's a few screenshots to show you in case I failed to explain: Windows:
Ubuntu (same key sequence):