I would get her a sampler from
http://metroemb.com/store/ mentioned above. Wherever you purchase the thread, it would be a good idea to include a color chart in the package.
I agree that she will also need stabilizer. I would get her a variety of stabilizers in small amounts so she can try the different ones out to see what she likes best.
Another great place to buy embroidery thread and stabilizers is
http://www.bobbincentral.com/quiltin...ead/glide.html but there are a lot of different kinds of embroidery threads there.