WSMonitor is a useful graph that will monitor the memory usage of  any open/running  flash app with a real-time graph.

Very Handy, here’s a direct link to download it.  (otherwise just google it)

http://www.websector.de/blog/2007/10/01/detecting-memory-leaks-in-flash-or-flex-applications-using-wsmonitor/

Hope That’s Helpful,

~Danny

Update: 5/3/2010, updated broken link, now working again.