Since the Nexus S, Google brought out the Galaxy Nexus, Nexus 4, and Nexus 5.
There is not a product from Google which is named 'Google I' There are however products such as Google TV, Nexus One, Nexus S, Galaxy Nexus, Chromebook and also Chromebox.
No
There are only a few differences between a Nexus S and a Nexus S 4G. Nexus S is T-Mobile phone, while the Nexus S 4G is a product of Sprint's Samsung. The only other major difference is that the 4G version offers Google Voice.
You can buy them at most electronics stores or online.
The Nexus S is no longer manufactured. The newest Nexus phones can be bought and used on the Sprint network.
Yes, if you buy the 3G version.
If you need a small tablet then yes!
From places such as the Google Play store and Android Appstore.
Yes, Buy them in the Play Store and download them with the Google Play books app.
Yes, most phones these days come with a web cam. The Nexus S has a Front-facing: VGA (640x480)
You can purchase one from Google itself (www.google.com/phone). Another option is the manufacturer, Nexus One.