For a good overview on astronomical spectroscopy, with many examples and objects, check out Christian Buil's website. It can be viewed here: http://www.astrosurf.com/buil/ [1] There are numerous examples under the "Obervations" tab. Kevin Paxson - PKV
Links:
[1] http://www.astrosurf.com/buil/
[2] http://www.aavso.org/forums/variable-star-observing/spectroscopy