You can look at their website for technical and correct information, this information might be a little biased towards their product, as they are trying to get you to buy one, but legally they cannot outright lie about their product. Another place you could try is Bestbuy or any other retailers that sell the product, they wouldn't be as biased as linksys.
One can get a Linksys Wireless G Cable Gateway WCG200 from many different stores. Some examples that sell this product include Memory4Less, eBay, and ZDTronic.
No, unless it has a router built into it. If a person is likely to want to connect more than one computer to the internet, they'll likely want a router anyway, thus rendering a second Ethernet port superflous. The Linksys WCG200 would be an example of a cable modem with a router built-in.