urldecode & header

hi i was wondering if someone can give me a hand (i'm very new to php). i have a form that user suppose to fill out that then get submitted to index.php (current setup) now what i need is another let's say index2.php that would take everything from that form, rewrite one of the field and spits it back to index.php now, i dont know but as far as i know stuff that form spits out is urlencoded, so i need to use urldecode function ( http://us.php.net/urldecode ) to decode and then header function ( http://us2.php.net/header ) to spit it back to index.php now after all that i'm pretty much stuck here, i dont know how to do it.. if someone can a spare a minute or two and write that code for me i'd highly appreciate that. thanks in advance -- http://alexus.org/