It is not possible to overclock n900 without changing kernel. This program can only set frequencies from available in system. If you are using default kernel you can only chose from 600 550 500 and 250. If you are using overclocked kernel then more frequencies will be available. Temperature is already shown on the Status tab. Free-form text for "Up Threshold" and "Sampling Rate" is not dangerous as system will ignore wrong values and before chosen value goes to system the limits are checked first and if it is out of limit then it is also ignored. Most of the main functions are finished so the first version will be released soon.