What are they made of?

Felted animal fiber. The figures pictured in this site were made from alpaca, sheep, angora goat, and rabbit fiber.
The fish in the wet felting section are wool felted over bars of soap. They can be used for hand washing or to add a soapy fragrance to clothes drawers.

What's on the inside?

Except for the soap fish all of my figures are felted fiber all the way through. I haven't used wire, foil or jointed armatures.

What are the details like noses and eyes made of?

Some figures have small beads for eyes, others have felt eyes and noses. Sometimes I add a few strands of angelena
fiber to felt eyes to add a little sparkle

How do you get bright colors.

I've tried Dylon and Rit dye but settled on KoolAid. For the small amount of bright color that I use I think KoolAid in my small crockpot works fine.

What kind of tools are required?

Felting needles

I started with the Clover 5 needle refill packs that are sold at fabric stores. There are lots of websites that offer more needle variety. I now keep seven different needles on hand.
38 star
38 triangle
38 close barb triangle
40 triangle
42 triangle
Clover Green
Clover Orange

Where do you get the foam.

You can find it at fabric and craft stores. It's foam like a seat cushion not styrofoam.

I save the packing material that they use to cushion things like laptop computers when they ship them.