The character palette is also available under Edit->Special Characters in most applications, or by the shortcut Cmd-Opt-T (or ⌥⌘T if you will).

Under Linux you can enable the compose key, with setxkbmap -option "compose:rwin"

This lets you prefix digraphs with rwin, and have them print unicode characters. This is (to some extent) configurable, although I am not sure on the location of the mapping.

EDIT: Some examples (default settings): ä ç ß ¢ £ ½ ⅓ ¼ ⅙ ⅛ » « ¥ õ ° — – º

Nope, just little blocks. Some interfaces display it as one solid dark monolith, some as empty squares, and a special few as festive little glyphs with mysterious markings inside. (XP SP2, every browser under the sun and then some.)

in windows xp with google chrome I just see box box box box box etc. In fact nothing on the blog displayed either.