From LedHed's Wiki
Contents
Installing Packages
pkg_add -r <PACKAGE_NAME>
-r installs a remote package (From the web).
Listing Installed Packages
pkg_info
This will list all installed packages, combine with grep to find packages you want.
Removing Packages
pkg_delete <PACKAGE_NAME>
Finding Packages
This is a little more difficult when compared to other package management systems like apt or yum.
I find the easiest way to get a list of packages is to search the ports tree.
find /usr/ports/ -iname "*<PACKAGE_NAME>*"
This will return all packages whos name matches <PACKAGE_NAME>.
Ports
FreeBSD has an extensive ports system which allows you to build custom packages with specific options for your system. See Ports
Reference
http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/packages-using.html