Hi all.. the other thing to consider, especially for MSN (and now with Yahoo) is embedding your keywords in the URL. For one of my website, WebmastersBookofSecrets.com, I already owned the URL so I was unable to embed the proper keywords. So, I made sure that my title included my keyword phrase after my URL. This seems to have improved my Yahoo and MSN rankings quite a bit. (ex: Webmasters Book of Secrets | Improve Search Engine Rankings).
The other strategy to consider is setting up a blog related to your site. I wanted to optimize for "Good Marketing Tips" and did so using a blogger URL (ex: goodmarketingtips.blogspot.com). Once the site was listed in Google, I placed a link to the before mentioned site using the proper link text. Again, this seems to have improved my Yahoo search results. I think its primarily because Yahoo likes links and it was contextually relevant.