Great Article on Unicode and Character Sets
It is easier as a developer who deals with English 99.9% of the time to overlook this stuff - especially in PHP - until you open and try to manipulate a bunch of .txt file not even thinking about the variety of Unicode formats. Found this rather enlightening …
Good for any PHP coder to read, especially as the documentation on this stuff at PHP.net is a bit on the lean side.
Update:Character Sets / Character Encoding Issues from WACT with lots of PHP-specific information.