Declaring multidimensional arrays in pl/pgsql

Hi, all.

I was wondering, can I really declare a 2-dimensional array of arbitrary
size in pl/pgsql?
According to the docs it seems that only way would be to declare it as
something like :
myArray := ARRAY[[1,2], [3,4], [5,6]];

But what if I pass the dimensions as function parameters?

My postgresql version is 8.1.

Thanks.