I think this is elsewhere on the forums, sigh, one more thing to add to the faq if I ever get time.
Apt-get is great, but it works with binary packages--FreeBSD primarily uses ports, which compile from source. This takes longer.
FreeBSD also has packages, which are binaries like Debian's apt. Sometimes, a package isn't made for a port, because no one got to it.
Sometimes, the packages are older than the port. Debian's software is often a bit behind too, as it goes through rigorous testing--this is why Deb has the reputation it does--rock solid stability but often a bit behind the times.
PCBSD has pbi packages. As it is only a few months old, at present, these are very few. There can also be conflicts with ports, as the packages don't register in /var/db/pkg, so if a package needs firefox, for example, and it's been installed through a pbi, ports will download and reinstall it.
One can upgrade with packages as well. First you have to install the portupgrade program.
Then, to upgrade only using packages, you use portupgrade -PP. This means use packages only. A single -P will use a package if available.
To do the equivalent of apt-get install for a new package, if there is no pbi for it, you can use pkg_add -r. This will fetch package if available from the FreeBSD site and install it.
Ports vs. apt-get.... apt-get is definitely faster, but ports will often give you a newer version of the package. Also, it is more configurable. Debian style packages can be configured, but it's non trivial. Configuring a port is fairly simple.
Hope this helps. Perhaps I'll add this to the faq over the weekend if I have a chance, as the question has come up a few times.