Is there some Milkshape exporter for Blender? If, yes it supports armatures and uv mapping?
nope, but there are other formats supported, even better, has milkshape does not support weights.
directx *.x format is supported, and that one supports weighs and bones, and is quite standard in most game engines. Still is a bit in the works.
we also have another , the md5 doom3 format , supporting weights and bones…
And using the vertex animation method, instead of bones, there’s the md2 exporter.
I saw this before but dont know how well it works:
http://guinness.cs.stevens-tech.edu/~acorriga/blender/
You could probably add some functionality to this if your missing something.