Stu,
My books from Amazon (see below) cover all the basic stuff you need to know about TAKING spectral images and basic processing.
Interpretation of the data is a much more complex learning experience!!
Kaler's book is a great starting point.
All you need to start is a grating (Star Analyser/ Rainbow Optics) a telescope f5 or above and a CCD camera...cooled mono preferred.
This will allow you to collect spectral data on thousands of stars, nova etc. etc. These lo-res spectra are great for learning your way around the basics of processing spectra (darks, background removal, wavelength calibration and instrument response.) Later you may consider moving up the "food chain" and investing in a slit spectroscope which, although more complex to use, can provide very useful detailed data for other amateurs and professionals.
I recommend looking at our Yahoo group:
http://groups.yahoo.com/neo/groups/a...ctroscopy/info
for more details (check out the files area) on spectroscopes (DIY and commercial) and basic methodology.
Hope this helps.