Realistic landmass and landscape formation?

[Wysardry]

Can any of you point me towards resources describing how to, or aiding in, creating realistic islands and continents, and/or landscapes for Earth-like planets?

Basically, I'd like to create a group of realistic islands (complete with detailed terrain), and do not have more than a vague notion of how they would be formed naturally or which shapes would be probable in reality.

Is there software available that can help with this process? I'm not even sure what search terms to use, or I would try Yahoo.

[Vaxalon]

I'm not sure if this one will go down to the level of detail that you want, but the best resource I've found for building worlds with versimilitude is the following:

In print
http://www.rpgmall.com/product_info.php?products_id=32785&

In PDF
http://www.rpgnow.com/product_info.php?products_id=2510&

I own the print version, and I find it a very useful resource for those rare occasions that the world I'm building follows real world physics.

[James_Nostack]

If you want to generate fairly realistic pictures of such terrain, might I recommend the free Terragen software?  http://www.planetside.co.uk/terragen/  

Terragen uses fractals and other computer gobbledy-gook to create randomly generated terrain.  Mucking around with it a bit can get you some really nice looking coastlines and islands.

What it doesn't do is show animals or settlements.  Shifting the color of the "land" though can give you a nice approximation of trees, grass, and so on, and the color palettes can be adjusted for "alien" worlds where the chemistry might be different.

What I am still looking for is some software that would map out an entire planet--either as a 3-D globe or as a Mercator projection.  That would be pretty sweet.

[contracycle]

Fractal Terrains will generate whole planets.  It produces islands, continental landmasses etc, and also precipitation, temperature and ecological bands.  But there is no terrain filling or anything along those lines, not vegetation and whatnot.

http://www.profantasy.com/Products/ft.asp

[Wysardry]

Wilbur looks quite interesting, and the site also has links to other terrain software sites.