Installing Emacs on BSD
Emacs is available on the BSD variants either in through precompiled binary packages or user-compiled ports. Installation instructions vary according to exact OS.
FreeBSD
To install the most recent prebuilt binary package of the (at the time) most recent stable version:
# pkg_add -r emacs
Or use the ports to build from source:
# cd /usr/ports/editors/emacs && make install
Developers may find "Using Emacs as a Development Environment," from the official FreeBSD project documentation, a good starting point. Some of the config tweaks are a bit dated and might need updating. But overall it's a reference
OpenBSD
Set PKG_PATH to an appropriate mirror.
# pkg_add -i emacs
pkg_add will prompt you for which version you want—currently, versions 21, 22, and 23 are available.
You can also install from the ports tree; however, "The [OpenBSD] ports tree is meant for advanced users. Everyone is encouraged to use the pre-compiled binary packages."(OpenBSD FAQ, section 15.3)
No premade port or package for Emacs 24 seems to be publicly available currently.