"Help" -> "Install New Software..." -> "Add..."

Location: http://download.eclipse.org/technology/m2e/releases/1.2/1.2.0.20120903-1050

该link获得方法：

浏览网址http://www.eclipse.org/m2e/download/，

得知：m2e 1.3 and earlier version have been removed from the main m2e update site. These old releases are still available and can be installed from repositories documented in http://wiki.eclipse.org/M2E_updatesite_and_gittags

浏览网址http://wiki.eclipse.org/M2E_updatesite_and_gittags，

得知：

亲测，安装成功！

Eclipse 3.7.2安装maven插件