php password encryption MORE secured?

Hi, I've read about md5 hash function and i've used it. Now to protect my database from hacking and stuff... I want to add additional hash function and concatinate it with the other.... just for the sake of adding more security?

$hashed = $md5($pass) '.' $sha1($pass);

somethin like that..not sure though... what can u suggest as a better method? or approach perhaps?

thanks

Actually one hash proves to be the best.

Collisions usually occur with random blocks of information. (Collisions are when two different words have the same hash)

Your technique works really well as nothing is rehashed.