I just updated the site to version 2.7 and received the error Cannot redeclare is_sticky()
This is caused by the Lester Chan plug-in Wp-Sticky
If you get the error, simply FTP into your WordPress installation and go to wp-content/plugins/ and delete wp-sticky
In order to use Sticky posts in WordPress 2.7, look under the PUBLISH section:
You need to select the EDIT option next to VISIBILITY and the Sticky Post option will appear like so:
This will place the post at the top of the front page for posts and keep it there after new posts are made.