You can provide fresh content to your websites with Clickbank products using this freebie:

ClickBank Product Feeds Delivered by RSS

ClickBank RSS Feeds – is a new technology to convert the ClickBank’s product database to behave like a news source (like Yahoo News).

I haven’t tried it out yet – just found it. I see that you can implement a keyword filter to match your content. Fresh content plus affiliate commissions, gotta love that!