Here is the link to login and download from official site. If you have an active subscription you may login to the official website and download your distribution from there. Different editions have different subscription charge. Red Hat Enterprise Linux being a commercial distribution is not free to download and use.
The first point update of latest stable release was released on march 06, 2015. The life cycle of Red Hat Enterprise Linux is 10 years. It is based on Fedora core 19, upstream Linux Kernel 3.10, Gnome 3.8 and Systemd 108. Red Hat Enterprise Linux 7, codename “Maipo” was released on June 10, 2014. Since the product is commercial-centric it is free as in speech but not free as in beer. Red Hat releases its distribution under various editions viz., Server, Desktop, Academic, Entry-level server (ES), Advanced Server (AS), Work Station (WS), etc. All the third party derivatives and community supported distributions be it CentOS, Oracle Linux and Scientific Linux build and redistribute their distribution by removing non-free components and Trade mark of Red Hat.
Red Hat Enterprise Linux provides their source code for free but keep check on free re-distribution of their officially supported version of Red Hat Enterprise Linux. Red Hat Enterprise Linux commonly but not officially abbreviated as RHEL is a Linux distribution developed from commercial point of view.