WordPress 2.9 is now available.
The new version includes plenty of new features on both the user and developer sides, including a global “trash can” for posts and comments, basic image editor, rel=canonical support, native support for post thumbnails (should your theme activate the feature) and an updated new Press This bookmarklet.
TechnoSailor has a 10 Things You Need to Know About WordPress 2.9 guide, which covers some of the more interesting features.
So take five minutes to upgrade your WordPress installation. Be sure to make a backup of your database first, since 80% of you probably don’t do it on a daily basis like I do. 
Hello. I try tweetable. but my web site is wordpress 2.9 now. Is tweetable OK? my version.
As far as I am aware, Tweetable works fine on WP 2.9. If it doesn’t work for you, be sure to let me know.