Google just announced a new service allowing webmasters to submit pages for inclusion into their index using an open source XML format dubbed Google Sitemaps. Google hopes the new system will help it do a better job of finding pages than traditional crawling alone allows. Feeds also let site owners indicate how often pages change or should be revisited. This will NOT replace the normal Google spider. It is only an additional method of retrieval for Google, and may be very useful for webmasters to help Google spider their dynamic URLs. For more information, go to Google Sitemaps Help or read Google's blog entry at http://googleblog.blogspot.com/2005/06/webmaster-friendly.html.
Use Yahoo's new Mindset to see whether a major search engine thinks your site leans more toward the informational or commercial. I played with the slider for a while for each of my sites, and was surprised to see how well each ranked based on Yahoo's impression of its informational/commercial qualities. What you discover about your own site might surprise you. Play with Mindset here.
If you use Firefox, you might find an extension called MeasureIt to be useful. With one click on a status bar button, you can draw a rectangle anywhere on a webpage and get the width and height (in pixels) of the area you drew. Great for seeing if an image will fit into a column, for instance. Grab it at www.kevinfreitas.net/extensions/measureit.
For a great place to get some technical tips, including dealing with server issues, 301 redirect code, using SSI on html pages, etc., check out www.bruceclay.com/SEO-tech-tips/techtips.htm.
If you are new to RSS feeds and feed readers, you might want to check out this great tutorial on effectively using Bloglines.