That is the main difference. Laptops can basically do everything a desktop can do, even play games when equipped with the proper IGP or video card.
Netbooks offer basic computing in a smaller packet and with Tegra 2 and AMD Fusion chipsets they will be able to rival Desktop PC's as well in terms of doing minor video editing, HD playback via HDMI out and even play some newer generation games, all in small package.
Notebook is just another name for laptop though some think it might be a laptop without an optical drive (DVD).
At least that's how I understand it.