As you can see, it isn't difficult to add rel="nofollow" in your existing outgoing URL's. Here are some additional tips on affiliate links.

• Mix up your anchor text - don't always use the same words for the link
• Have affiliate links open up in a new window - add this:
• target="_blank"
• Don't add too many affiliate links within a page as it may seem desperate
• Add your affiliate links at the bottom of your page instead of the top - this gives readers a chance to actually read your content before they click