Use the {update} keyword from hg-prompt.
    
        | author | Steve Losh <steve@stevelosh.com> | 
    
        | date | Thu, 23 Jul 2009 02:44:50 -0400 | 
    
    
        | parents | 8a98384e2659 | 
    
        | children | 39fa52b2fe24 | 
    
        | branches/tags | (none) | 
    
        | files | .bashrc | 
Changes
    
--- a/.bashrc	Thu Jul 16 03:26:52 2009 -0400
+++ b/.bashrc	Thu Jul 23 02:44:50 2009 -0400
@@ -44,7 +44,7 @@
 ORANGE=$'\e[33;40m'
 
 hg_ps1() {
-    hg prompt "{${D} on ${PINK}{branch}}{${D} at ${ORANGE}{bookmark}}{${GREEN}{status}}" 2> /dev/null
+    hg prompt "{${D} on ${PINK}{branch}}{${D} at ${ORANGE}{bookmark}}{${GREEN}{status}}{${GREEN}{update}}" 2> /dev/null
 }
 
 export PS1='\n${PINK}\u ${D}at ${ORANGE}\h ${D}in ${GREEN}\w$(hg_ps1)\