TIMEZONEC

Well, I wanted to have more security around my house and I was wondering what kind of cameras are good? I want something that can be seen at daylight and at night time. The cameras will be inside and looking into the outside. Also, all of this information will be on my computer and sometimes when I'm out, I would like to go back to the video and see what happened and so on...For this will I need a big harddrive storage? I will be installing about 4 cameras around the house? Will wireless or nonwireless be good? What should I lookout for? I know most of these have already been asked but ya...sorry for my English:) *EDIT - also what about psu's? and are there like professional people for this to protect your house or is it safer to do it on your own?

no suggestions or help?