WordPress 2.7 “Coltrane” is finally out. And designers, you know what that means: time to update those themes! Old ones shouldn’t break with the new version of WordPress (if you’ve updated them for WP 2.6), but it’s an added incentive for bloggers to download WP 2.7-ready themes.

Read the WordPress Codex article on Migrating Plugins and Themes to 2.7 and these 3rd-party tutorials, then add your theme to the WordPress 2.7 Compatible Themes page. You should be all set in no time.