Pretty good showing off, Setanta.
Yes, it's called "umlaut"(vowel) and besides the ü, we also have an ä und an ö
When my daughter started learning German she especially liked the doted
"umlaute" as she was convinced that they're the happy version of the regular vowels.
Für Elise is one of my favorites, such a beautiful piece of music.
I have a Mac, so for me it's option+u+u, or option+u+o, and option+u+a