m2e is only included in the Java developer version of Eclipse, as you can see on this page ("Maven" topic): http://www.eclipse.org/downloads/compare.php
However, an easy way to get m2e is through the Eclipse Marketplace:
Go to Help -> Eclipse Marketplace and look for m2e. Click "Maven Integration for Eclipse", then on Install (or drag and drop the install link to your running Eclipse workspace if you opened the marketplace in a browser), et voila!
Direct browser access: http://marketplace.eclipse.org/content/maven-integration-eclipse