Looking For PHP/AJAX Vote Up/Vote Down Script

I’m looking for a script that can be used to vote up(thumbs up) and vote down(thumbs down)
posts, similar to that used at stackoverflow, preferably free.


do you use any specific platform like wordpress.
if wordpress then there are lots of voting plugins available

well this one is paid but interesting

See this Ajax Voting Script. It is free, and with vote up /down buttons.
Data can be saved in TXT files on server, or in mysql database.

Thanks. That’s what I was looking for.