All the flags are:

• [N]New
• [D]Deleted
• [*] Important
• [A] Answered

[^T] Can be used to see all the flags and set/unset them one by one (or all).

Due to the licensing rules of Pine (and Pico) these are not included as deb packages in the mirrors.
However the source of these two are.
Step 1 is to ensure that you have a deb-src in /etc/apt/sources.list (for instance)
deb-src http://http.us.debian.org/debian stable main contrib non-free
deb-src http://non-us.debian.org/debian-non-US stable/non-US main contrib non-free
To make Debian install from sources:
If you have never installed from source before we need to install a compiler and dpkg-dev
$apt-get install dpkg-dev
$ apt-get install gcc
Done, now we can start compiling Pine
A short note now: When building from source apt will download the source (and compile) to the directory where you start from. I think it is nice to make sure you are in a new directory that is clean from other files (and at a logical location if you intend to save the compiled package (like for instance /src/pine)
$ apt-get -b build-dep pine

$apt-get –only-source -b source pine
(now it will download and compile Pine. Be patient.
$ dpkg -i pine_4.64-3_i386.deb
Another option is downloading a deb package directly from Washington University here

Any program in the Debian archive can be compiled from sources using the steps above, important to note is that in “apt-get -b build-dep” -b means build from source and build-dep that apt should download any libraries that is needed at the same time.