Harry Fuecks from SitePoint has put together what looks to be a very handy library to allow PHP manipulation of UTF8 strings.
Historically whenever PHP has been given the task of changing UTF8 encoded strings (ie. form entries that your users input) it's not given out any nice in return. Full support is due in PHP6 but that is still a wee way off (and I bet there are a few of you still using PHP4).
So for the PHP coder who has been missing out until now got and grab Harry's new library.