Some good database character-encoding advice from Mathias.
A very handy looking API that turns file uploading (and conversion) into a service.
A handy page for looking up HTML entities.
A very useful tool for getting character entities (use the "as HTML" option) in one click.
An offhand remark I made on Twitter spurs Dom on to do a whole lotta research on character encoding in class names.
This article is a life-saver for me. I'm constantly having trouble with special characters when I'm backing up databases for local copies of my sites.