Last week I wrote a Server Memory monitoring tool using Flash Remoting. I'm not much of a flash developer, but it only took a few hours. Here's a screen shot of the tool:

Keep in mind this tool only shows the memory for the JVM instance that ColdFusion MX is running in.

Here are some code to find out some info about the memory usage of CFMX or BlueDragon. The Java API provides three methods in the java.lang.Runtime class: freeMemory, totalMemory, and maxMemory.