I just read on engadget.com about the new iPod touch. New iPod Touch is essentially an iPhone minus the phone part, but it adds in WiFi so you can connect to 802.11b/g networks. It includes Safari and a special icon for YouTube specifically. Battery life is claimed to be 22 hours for audio and 5 hours for video.
iPod Touch can also buy songs directly through WiFi without the need to be hooked into a computer but it will sync songs back to iTunes when the two are connected.