sorry for my fast, snappy reply earlier. if i knew more what you're looking for, i could give you a better answer. at the moment i'll just assume you could take care of a v1 or v2.
_tama_cream_soda_ is right, there are 4 snack choices and 4 meal choices that stay there all the time, and you can buy more. about the shops changing, i think that's right--i'm not exactly sure what is meant by "changing" but they restock at, i believe, 3:00 and 6:00 (not sure about those times).
however, the things that you do to actually care for the tama (feed, train, bathroom) are pretty much the same, and if you have one, you should be able to figure that out.
i can't help if you want to know more about connecting, as i've never connected mine yet.
some extra features include:
-souvenirs (items you get off tamatown, mostly)
-ability to "connect with the computer" i guess you'd say, or get stuff from tamatown.com
-extra games
-extra characters
-ability to look up what characters you've had on each generation
-sales in the shop
etc
at the moment, that's all i can think of.