a few tips for those willing to develop UTF-8 based web applications:

-I've had great great results with mysql 4.1 (utf-8 native) and php 5 with mbstring, works smoothly

-Beware that php itself can only be written in iso-8859 (variables, functions...) so if you need to write some stings (error messages for example) in your scripts, better store them on seperate text files or in the database

-Beware that some editors add a header line called "UTF-8 signature" to text files wich might cause you some headecks with php and other parsers

-URL encoding and decoding Data is a good way to manipulate UTF-8 data in a non UTF-8 environnment and to exchange data between php and javascript

-Always add accept-charset="UTF-8" to your <form> tags

-Always use Binary transfer in FTP, ALWAYS :)

hope it'll help some