A C# library to read and write files using the NBT format described on http://www.minecraft.net/docs/NBT.txt
This is pretty much only useful to people making support utilities for Minecraft.
If you need a different license put create a feature request on the issue tracker and I'll probably be willing to.
I didn't see a way to add more licenses but you can also use the source under cc-by-sa.
I'll update if there are bugs, but this is pretty much done.
The api is pretty obvious, but here's a head start.
If you want to load from a file use the static method TagCompound.ReadFromFile(filename). If you want to save to a file use the instance method TagCompound.WriteToFile(filename).
Also for streams use TagCompound.Write and AbstractTag.Read.