Red Hat Enterprise Linux is a Linux distribution produced by Red Hat and targeted toward the commercial and enterprise market.
Red Hat Enterprise Linux is often abbreviated to RHEL. New versions of Red Hat Enterprise Linux are released every 18 to 24 months.
Note: Verbatim copying and redistribution of the entire Red Hat Enterprise Linux distribution is not permitted due to trademark restrictions (source: Wikipedia).
Some pointers, for those developers who need to interact/collaborate with RedHat RHEL package maintainers.
General information
RHEL Product Homepage: Red Hat Enterprise Linux
RHEL Customer Portal: Whats New, Knowledge Base
Wikipedia: Red_Hat_Enterprise_Linux
Software/Packages
Information about package/projects: TBC
Find source packages: ftp.redhat.com
Find binary packages: TBC
Bugs
Bug Tracker: bugzilla.redhat.com, Submit a bug
Bug Fix Advisory Tracker: Red Hat Product Errata - Bug Fixes
Security Updates
Security Advisory Tracker: Red Hat Product Errata - Security
See also
Fedora (Red Hat sponsored community edition): Fedora
CentOS (Open source re-implementation of RHEL): CentOS
Guidance for migration from RHEL to Debian: LinuxMigrationToDebian
Guidance for Debian Developers collaborating with other distributions: DistributionsCollaboration