Electric shaver or a razor?
I use a razor and like it that way. My friend uses a 3-blade Electric shaver type and says it's best.

What is the frequency of shaving?
Shaving your head every 3 or 4 days will keep you looking and feeling good. If you do it every day it will be perfect.

How can I know that it will be appropriate for my head?
Usually, if you have a hair-loss problem you should shave your head anyway, but if you are not sure you can always look at the HairStyles for balding men Gallery to find someone who looks like you. Or try virtual HeadShaving on if you want to see how would you look like bald, for free.

More great resources are Baldlygo's Forum, headshaver.org - all answers about HeadShaving, headshaveproducts.com, where you can talk with other shaved guys. Try also Creocut.com message board to consult and find some answers.