[quote:38d0opvc]The current problems are-
Inability to generate large worlds.
Cannot implement fluids(lakes etc)
Saving and loading.(trees cannot be saved as there is no info about them in the array)
To get a large world you can set perlin to a larger size... say 100 x 100, then set your loop to 50 to 100 for another layout.... using the same seed.
Not sure what your looking for in terms of fluids, but the cap shows one possibility while showing a possible optimization using one sprite set to different frames.
http://dl.dropbox.com/u/666516/perlincraft.cap
Keep in mind you've only used the positive values in the noise. There are a few things you can do with the negative as well.
As far as trees... All I can think of is making an array of all the created sprites, and then saving, and loading it as an external array.