You can definitely make some good cash affiliate marketing using PPC programs like Adwords.
I generally don't give out campaign stats - but this campaign has been well and truly slapped. This was one of my better campaigns - over $8k NZD was spent on it and I got nearly 150k clicks from Google. My landing page CTR was around 80% and I got a conversion rate of between 5%-10%. Thats around 6000 to 12000 leads at $1.25 USD payout.
I tend to go for the lower cost per click niches and focus mainly on the content network. I haven't really done anything bigger but there is money in most niches. It can take a long time to start making some real cash with Adwords but once you get it... you can keep on doing it.
If you want to learn I'd go with something like PPC Coach.
Programmer, web developer and entrepreneur.