MemoryCell is a MenuExtra for OS X that provides a quick overview on the memory (RAM) being used by each of your applications. With MemoryCell, you can monitor the memory usage of the foreground application, using this knowledge to restart anything that’s started to bog down your system.
Full Mac OS X 10.5 (Leopard) Compatibility, Full Intel support
Operating Systems: Mac OS X 10.4.0 – 10.5.1. Architecture: PowerPC, Intel
Download: MemoryCell 2.1 for Mac OS X