<http://www.php.net/manual/it/function.mt-rand.php> says:
"assicura numeri casuali che dovrebbero essere adatti per scopi crittografici"
which translates to sometihng like "it cerates numbers that surely can be used for cryptography"... at it is plainly false and negated on the homepage of MT itself.

don't know if this is just a translation of an old verison of the english page, but right now the english page says the correct thing: "can be used to seed..."

A better italian translation would be:
"genera numeri casuali che, con le dovute accortezze, possono perfino essere usati in crittografia"

Anyway I'd rather REMOVE that citation of cryptography entirely from every translation, as it is not adequate for it (MT page also says it in the first lines: "Caution: MT is for MonteCarlo, and is NOT SECURE for CRYPTOGRAPHY as it is.").
As they say in the FAQ <http://www.math.keio.ac.jp/~matumoto/efaq.html> "changing a linear congruential PRNG for MT can do no bad" but this is far from being "cryptographically secure".

A good secure PRNG is Bruce Schneier's Yarrow <http://www.counterpane.com/yarrow.html>
Also a good text about security and PRNG is linked in that page: <http://www.counterpane.com/pseudorandom_number.html>