I am currently running WordPress 3.0 using the K2 theme nightly version 1.1 r1105. When I previewed the theme first the format was not showing up correctly. I had to re-select ‘Use K2 Styling’ in order for the site to be displayed correctly. I only mention this because on two other sites with a different hosts I did not have to do this. Strange – no matter everything is working.
Also, I had to re-select ‘Header Menu Home tab’ selection of Custom and re-enter ‘Custom Home tab’ name: Start under the K2 Options tab.