Sswift has a perlin noise function in the code archives, you'll have to have a route around to find it. I've never tried Sswifts one but if it's anything like the rest of his code it should be pretty good.
Perlin noise basically means you get a random height map then smooth it to hell using interpolation. There are linear and cosine interpolation functions in the code archives too. Once you've got your first lump of smoothed random numbers you then do it again but with more numbers and plonk the new lot on the top of the old and so on and so on, these are called octaves.
Anyway... you probably don't need to know and/or care about any of that, find the code archive and you should be sorted.
Perlin noise basically means you get a random height map then smooth it to hell using interpolation. There are linear and cosine interpolation functions in the code archives too. Once you've got your first lump of smoothed random numbers you then do it again but with more numbers and plonk the new lot on the top of the old and so on and so on, these are called octaves.
Anyway... you probably don't need to know and/or care about any of that, find the code archive and you should be sorted.