We have just had a paper published on UniChem - simple name, simple functionality, but we love it, and it has become the way that we map ChEMBL to other data sources and keep things linked in real time, and also keep the ChEMBL molecule tables manageable. It's published in the Open Access Journal of Cheminformatics.
There is an interface on the above UniChem link, but for most use we anticipate REST web services access - details are on the link above.
The link to the provisional pdf is here.
One of the jolly blog pixies is writing a blog post showing some use cases for UniChem - and I have a lovely thing called "Chive" to tell you about in a few weeks!
%T UniChem: a unified chemical structure cross-referencing and identifier tracking system %A J. Chambers %A M. Davies %A A. Gaulton %A A. Hersey %A S. Velankar %A R. Petryszak %A J. Hastings %A L. Bellis %A S. McGlinchey %A J.P. Overington %J Journal of Cheminformatics %D 2013 %V 5 %O doi:10.1186/1758-2946-5-3