There are so many chemistry sites on the web that no list can begin to summarize them. Googling for chemistry sites is the best strategy. This short list is highly selective. It contains a few major "portal" sites, and contributed sites set up and maintained by Canadian chemists. The focus is on sites that organic chemists will find useful, and no attempt is made to be encyclopedic.
An excellent list of chemical societies worldwide is maintained by the Royal Society at http://www.chemsoc.org/societies/society1.htm.
Natural Sciences and Engineering Research Council (NSERC) of Canada
Canadian Institutes of Health Research (CIHR)
National Research Council of Canada (NRC)
Many index pages come and go each year, and rapidly become outdated unless they are actively maintained. Here are a couple of sites that have proven themselves over many years.
Chemdex.org: an international directory of chemistry on the internet, maintained by the University of Sheffield (UK).
Links for Chemists: the chemistry section of the WWW Virtual Library, maintained by the University of Liverpool (UK).
References for Organic Chemists from the WWW Virtual Library.
Named Things in Chemistry and Physics (compiled by John Andraos - York University).
WEB-ster's Organic Chemistry: Nick Turro (Columbia University) and Ron Rusay (Berkeley) have compiled a variety of links and teaching tools here.