RSS Generator using PHP
 

Hi there,
i'm trying to make a RSS generator using PHP for my final project
can somebody point me some script i could use to generate this?

the system uses 1 form to input URL, and the sistem will parse that URL to generate a new RSS feed, just like http://www.myrss.com.
to limit my project, i can limit the sites that can be generated, but i think it is possible to do some tricks to get this systems works on all sites that has news and can be generated by RSS

thanks b4