As with all character meals, the Princesses will greet Guests at their tables during their meal. The one exception to this is Cinderella herself who actually is in the lower lobby before you go upstairs. She likes to welcome each Guest to her restaurant personally!
Cinderella's Royal Table is an expensive table service restaurant located on the mid-level of Cinderella Castle. It has some good views over Fantasyland, and and is themed to something that personally, I feel, belongs more in Sleeping Beauty than Cinderella. The style is more medieval looking that 17th Century French! The food is good, but is very pricey. There are better places to eat, and the Princesses are so common, that this isn't really a must see, sadly.