I must agree with Darkhog that Wiki pages sometimes doesn't offer easy understandable explanations.
While the base idea of wiki pages is to provide easy explanations to comon pepole I find it more and more often that they are written for more scientific audience (lots of scientific teminology). This of course make wiki explanations les understandable and actually forces you to read explanations for all that scientific terminology.
So in the end you can quickly wind up reading half a dozen wiki pages just to understand one thing.

Now as for Perlin noise generation the wiki article didn't helped me much to understand how it works. But I did managed to understand it quite good after readin Ken Perlins oficial explanation of Perlin Noise Generation. You can find it here:
http://www.noisemachine.com/talk1/
Another two great sites explaining how perlin noise works are:
http://freespace.virgin.net/hugo.eli...s/m_perlin.htm
http://webstaff.itn.liu.se/~stegu/TN...-math-faq.html