IE 8 is the most standards compliant and feature-packed version of IE that is currently in Beta. If you are a web developer, you owe it to yourself to know how the changes will impact what you are currently building. Getting conversant with the new version can also help you plan for your future releases.
To stay updated on IE developments, the IE Blog is the best resource. It was recently announced there that folks in the IE Team have authored articles for a special issue of Code Focus magazine. It is a available as a PDF file (7.2MB) & there are some interesting articles in it. Go grab it.
Also see: Free ebook - Firefox 3 REVEALED