Doesn't "Start-Menu-> Settings -> CPU-Settings -> Set the default MHz" store the value permanently for you?
And "Start-Menu-> System -> CPU-Speed" shows the current value and let's you modify it for the current session.
And if by "command" you mean a terminal-command, then "cat /proc/pandora/cpu_mhz_max" shows the current cpu-speed. I understand the "max" in there as "the maximum that the cpu runs on automatically when that performance is needed". It might currently run with less when the cpu is idling a lot.