--- /home/cleyon/u/share/emacs/site-lisp/org-6.09/lisp/org.el	2008-10-09 10:25:12.000000000 -0400
+++ org.el	2008-10-16 21:57:45.000000000 -0400
@@ -2511,11 +2511,12 @@
 		      (apply 'encode-time (org-parse-time-string te)))
 		     (time-to-seconds
 		      (apply 'encode-time (org-parse-time-string ts))))
-		h (floor (/ s 3600))
+		sign (if (< s 0) "-" "")
+		h (truncate (/ s 3600))
 		s (- s (* 3600 h))
-		m (floor (/ s 60))
+		m (truncate (/ s 60))
 		s (- s (* 60 s)))
-	  (insert " => " (format "%2d:%02d" h m))
+	  (insert " => " (format "%s%d:%02d" sign (abs h) (abs m)))
 	  t))))))
 
 (defun org-check-running-clock ()