Tasky is a free Symbian Signed task manager for Symbian 9.1 based Nokia S60 3rd Edition devices like Nokia N80, N93, etc. The software claims to monitor processes, threads, RAM usage for a process/thread, PID and UID of a process. It can also compress memory (which I think is just for the heck of it) as well a kill a process or thread.

Download Link- http://www.telesoftas.com/binaries/Tasky_S91_SDK_SERIES60_FP3_signed.sis