May someone suggest me some good affiliate program script in asp or php?

I can't make any personal suggestions unfortunately :(
However, I would suggest having a look on HotScripts (http://www.hotscripts.com)
Depending on both your budget and your requirements you should be able to find something.
You might also have a look on SourceForge (http://www.sourceforge.net)
I remember seeing scripts on one of them that were geared specifically to webhosts/ISPs, but I can't remember the details.
You might want to look at the Perl section as well.