It’s especially a problem on Windows computers with U.S. keyboards – the only option is to cut-and-paste from Character Map or remember the awkward alt-numeric-keypad codes.
The Mac is really nice in this respect – U.S. keyboard? Type Option-n, n and you get ñ. Type Option-i, some-letter, get an accented letter.
Another option is changing the keyboard settings, but that only works if you know where they key is supposed to be!
