Since I am about to take my first baby steps in the world of borosilicate, I have been doing a LOT of researching and reading! I came across the articles page on Drew Fritts' website and have found a lot of the information really useful!
Here's the link:
http://frittsartglass.com/marbles/articles/Articles.html
The beginners guide to Glass Alchemy colours I think will come in very useful!
This - http://www.zandstormshop.com/docs/boromax%20tutorial.pdf (http://www.zandstormshop.com/docs/boromax%20tutorial.pdf) is also really useful as a starting guide to boro colour.
You might find both contain quite a few colours that have disappeared since they were written but the principles are the same :)