Performance Monitor for OS X? (free)

Hey all,

Trying to find a performance monitor for my new little iBook, just to get an idea of how much memory, CPU, &c. is being used at any given time -- akin to /usr/bin/top, but with a graphical interface.

iPulse looks cool, but it's $12.95. Is there a free one out there people can recommend?

Thanks!

activity monitor does a lot of those things. it comes with OS X. applications>utilities>activity monitor.

I like to use 'X resource graph' and 'Menumeters' is also good. Both of them are free.