PHP: preg_match_all with multibyte characters?

Hi! I'm trying to separate text into sentences, like this:

$pattern = "/[A-Z]([a-z]|[[:space:]]|,)*[\.\!\?:]*/";
preg_match_all($pattern, $text, $matches);

This works fine unless the text contains multibyte characters, like "���". How can I make this work with these exotic characters?

An example phrase that doesn't match:
"Detta �r ett test!"
The character '�' prevents a match, but I would also like to match those characters.

Check your locale and if it doesn't work, have a look at the PHP mutlibyte string functions.
PHP: Multibyte String Functions - Manual

Or wait for PHP 6 that should have native multibyte support for the PCRE functions.