Many poker players in USA, Canada, Australia, UK are awaiting PokerRoom.com to reopen its tables and tournaments before the end of 2011 as of some latest twitter.com/poker rumors.

old pokerroom.com table
If the table you want happens to be full, there is a waiting list you can sign up for. You will get notified as soon as there is a seat available. In the meantime you can play at any of the vacant tables.
Besides “physically” joining a table, and being represented by a cartoon character, there is always the option to just watch. Then you will not be able to chat and there is a 10-minute time limit, after which the window will close and you go back to the menu.
As usual, a page like this cannot provide a complete description of the game, but we think you will get the hang of it after playing a few hands. Good luck!