• NIH PubChem provides information on the biological activities of small molecules. It is organized as three linked databases within the NCBI's Entrez information retrieval system: TPubChem Substance, PubChem Compound, and PubChem BioAssay.
• Spectral Database for Organic Compounds, SDBS SDBS is an integrated spectral database system for organic compounds,which includes 6 different types of spectra under a directory of the compounds. 
• EPA Reference Absorbance Spectra The spectra listed here were created from the interferograms in the EPA Reference Spectra Interferogram section

*Great chemistry guide at http://en.wikibooks.org/wiki/Chemical_Information_Sources

This is a subpage of the Physics, Chemistry, Astronomy, Math page, which you should also consult.