Synthetic Pages http://www.syntheticpages.org/
Free interactive database of practical and reliable organic, organometallic and inorganic chemical syntheses submitted by synthetic chemists.
The ChemExper Chemicals Directory http://www.chemexper.com/
A catalog of 60000 fine chemicals searchable for free using a chemist-friendly search engine. Products are listed with physical data including IR spectra and MSDS. Contributions to the database possible with dedicated (and free) program.