After installing 3.0b, this appears at the top of every admin page:
"Warning: Call-time pass-by-reference has been deprecated - argument passed by value; If you would like to pass it by reference, modify the declaration of do_action(). If you would like to enable call-time pass-by-reference, you can set allow_call_time_pass_reference to true in your INI file. However, future versions may not support this any longer. in /wp/wp-content/plugins/sitemap.php on line 1631"
-- Charles Wiltgen