How To Use The Multiplier Effect In Web Marketing describes how to use free eBooks and writing eZine articles for others' eZines to build traffic and links to your website. They also mention link exchanges--just be careful it you do that not to get involved in "link farms", where links are exchanged in bulk between completely unrelated websites. Google will reduce your PageRank if they find that you're involved with link farms.

I had no idea that there were established systems for submitting articles for others' eZines. Publishing this way can get your articles in front of many readers without your having to maintain an eZine and build a subscriber base.