Can you go on the Internet with the Amazon Kindle 3G+Wi-Fi?

I'm planning to buy the amazon kindle 3G +Wi-Fi costing $164. I was wondering if I can go on the Internet with it. For example, will I be able to go on my gmail account wherever there is WiFi? I would also appreciate it you could explain any other features regarding the type of kindle i'm going to buy. Plz help!! Thxx