Mercurial Eclipse Plugin
Where can I find a good Eclipse Mercurial Plugin?
MercurialEclipse
Update site: https://bitbucket.org/mercurialeclipse/update-site/raw/default/
Installation manual
As stated below (in comments) the name is MercurialEclipse. The name HgEclipse was a fork that Intland did and was later "merged" back again with MercurialEclipse, which moved around a bit between the current site, Google code and javaforge.com.
Vectrace is dead. They say you need to go to javaforge ( http://cbes.javaforge.com/update ).
WARNING: plugin on javaforge is unsigned and cannot be verified.
Update 2017-May-6: the below is no longer applicable, the accepted answer has been updated.
I think the accepted answer is now outdated, what's available in the 'Market Place' does not work when adding a repository with latest Java 1.8 x64 (Issue #60) - was hoping installing a the snapshot would help but it did not.
http://mercurialeclipse.eclipselabs.org.codespot.com/hg.wiki/update_site/snapshots
MercurialEclipse 2.1.1.201401121312
Here are the other versions found:
http://mercurialeclipse.eclipselabs.org.codespot.com/hg.wiki/update_site/stable
MercurialEclipse 2.1.0.201304290948
http://hge.javaforge.com/mercurialeclipse-snapshots
MercurialEclipse 1.9.0.201106191824