You won't be able to hide the numbers in you contact list, however if someone calls you that you want kept hidden. The phone will not ring and no notifiaction will appear. You can set it to only accept calls/SMS from your contact list or a specfic number. After you install it, cut the shortcut from the Window\Start Menu\ folder; and paste it directly in the Windows folder. When you want to review who called or SMS you. Just go to the Window folder, enter the password and and select View Log. Its called Magicall and it works great.
http://www.mobiion.com/magicall.html