Timac has released Cornichon (http://www.timac.org/cornichon/), a tool you can use to dynamically profile Mac OS X applications on the system and track the process’ performance over time (CPU usage, resident memory size, total memory size, etc).
The Cornichon application includes the ability to see the different collected data of a process in real time in a graph and export the data as TAB files that you can later easily import in Apple Numbers or Microsoft Excel.
Cornichon requires Mac OS X 10.5 or later. It costs approximately US$7.