Andrew explains how he uses Growl to monitor long checkouts. Here's an additional growlity that I use to track Cocoon's lengthy build process (I want a MacBook!):
build.sh $* && growlnotify -m 'Build done' -t Cocoon || growlnotify -m 'Build failed !!' -p 2 -t Cocoon && exit 1
The "-p 2" displays the notification in red (I configured it the Growl control panel for the "emergency" level), and propagating a non-zero exit status allows to chain the build with another command. I named the above script "buildc" and can therefore write:
buildc && cocoon.sh servlet
Sweet Mac, that smoothly integrates a unix for us geeks and a nifty GUI for us artists :-)