The UC Irvine ChemDB
Try out the free UC Irvine ChemDB! Nearly 5 million compounds can be searched by structure or properties. ChemDB includes free online cheminformatics tools such as Babel file format conversion, SMILES depict, and molecular property calculation as well. Read more athttp://cdb.ics.uci.edu/CHEM/Web/ and in the following papers
Bioinformatics 2005 21(22):4133-4139
Bioinformatics 2007 23(17):2348-2351
Free ACD/ChemSketch Licenses to All Academic Institutions
Advanced Chemistry Development (ACD/Labs) donates free ChemSketch licenses to academic institutions.
More information at http://www.acdlabs.com/educators/chsk_licenses.html