I'm not quite sure what you mean by account.
If you are talking like on the Xbox, where you have to buy live, then no. All you have to do is create a username and you can start playing!
If you mean to you need to have internet service and an internet provider then yes you can not use the internet without someone having internet service.
Yes, Call of Duty: Black Ops will have online multiplayer just like many other Call of Duty video games.
You can play online in Call of Duty Black Ops PS3 using the online split-screen support.
Yes
You need an online connection and an account for the Playstation Store or Xbox marketplace
yes it will.
you have to get it online.
You cant.
There is online for Call of Duty Black Ops Zombies.
Yes it is.
No. but you can play call of duty blacks online on a PC
If you get call of duty black ops there is a zombie mode and you can play it online.(There are other call of duty's with zombie modes.)
Call of Duty Black Ops is four player split-screen, and 2 can play split-screen online.