I am using Panasonic BL-C30. It is wireless but no zoom or voice. The setup is easy and the picture quality is quite good. But i remind you to try your friend's ip cam in your office before you buy because lot of company block some of the ports.
"容唔容易" depends very much on computer literary, and it is quite similar for all IP-cams. So if you are not familiar with networking, you'd better pay more for the installation service.