A Pavlova is basically a giant merangue (although you can make small versions that won't take as long to bake) that has a firm outside and a almost soufflee like interiour. I don't know what makes it this way - I've had merangues that are firm all the way through with very little differentiation in the texture (read firm, hard, often on the verge of being brittle), but the good ol' pav (pavlova) has this incredably supple texture.
The idea is that you have this egg white base, and then you pile in freshly whipped cream and fruit. The pav's that I grew up looking at I never really like. They were filled with strawberries, maybe raspberries and passionfruit all pilled on top to resemble something that one regurgitates rather then ingests.
For the pav here, I simple used whipped cream with a touch of vanilla and sugar, a raspberry coulis (simply frozen raspberries from summer simmered with sugar and a smidge of lemon juice and strained through a sieve) with some kiwi fruit and persimmons on the side. It worked out pretty well - I'm looking forward to trying this one in Summer with beautiful fresh berries.
For the recipe I used see Smittenkitchens blog: http://smittenkitchen.com/2007/04/a-ballet-of-sorts/