You PC players are lucky. I don't usually buy DLC, but will make an exception for this! Have to wait a few months for PS3.
There are a lot of people here who have played Demon's Souls/Dark Souls. I bought my PS3 specifically for Demon's Souls. If you have any questions I or anyone else would be able to answer them. Only tip I can give is to not care about dying. The sooner you can accept death and loss of souls you will enjoy the game(s) more.