I have heard of people using some kind of transfer pipettes, and other people using syringe-type devices. I have never used either for paint, but I had to use a graduated syringe type tool for administering medicie to my cat, and thought it would work excellent for measuring paint.
You can pick up either from medical supply places, and I think I have seen transfer pipettes at the hobby shop near the paint. They look like a plastic cylinder-bulb with a straw attatched.
Kevin