I just upgraded to Eclipse v4.2 (Juno). The Maven plugin seems to be missing. How do I get it?
All the info you need, is provided in the release announcement for m2e 1.1:
m2e 1.1 has been released as part of Eclipse Juno simultaneous release today.
[...]
m2e 1.1 is already included in "Eclipse IDE for Java Developers" package available from http://eclipse.org/downloads/ or it can be installed from Eclipse Juno release repository [2]. Eclipse 3.7/Indigo users can install the new version from m2e release repository [3]
[...]