I think you're all being silly
If he even just worded the post differently, along the lines of:
"I'm using phpnuke and want to display a site in an iframe, but it'll need php to load up the sites url from the database, depending on what link the user clicked to get to the iframe page... how do I do that?"
Then I bet you wouldn't be moaning so much... it's only because he said it in a slightly more demanding way...
I've never used php nuke so don't know exactly where the desired website URL to go in the iframe will come from. Otherwise I'd help and post the code here, for everyone to see. So there'd be no personal gain, just gain for everyone who wants to know.
TBH you did pretty much bully him into saying he'd pay - telling him off for asking for it, then to counter the personal gain argument he said he'd pay, then you moaned about that too
Plus the copyright/legality of showing another site within yours... it's totally legal. To make it illegal, you'd have to load up the contents of the website and display it in your site without any of their branding, etc. An iframe will show their website exactly how it's supposed to be shown - just in a frame. No legal problems there at all.
Also, frames aren't
always bad IMO - they are bad to base your website design around, but there are often some good reasons to use them, and tbh I think this is one of the good reasons to use them - when you don't want people leaving your site.