MikTeX and TeXLive are not TeX packages but distributions. Both implement basically the same compilers. Both take the packages (the files you include with \usepackage) from CTAN. These are independent from the distributions. However, some (newer) packages might be not (yet) included in one distribution. But there should not be any difference for "normal day-to-day use".
What is different between these two distributions is how they allow you to update packages, i.e. which user interface they give you in addition to the normal (La)TeX compilers. MikTeX for example allows the automatic installation of missing packages on-the-fly. AFAIK it is also more optimized towards Windows users. TeXLive is provided for other OSs as well and is therefor less Windows specific. You might want to use MikTeX on Windows because of that. TeXMaker should work fine with both.
Well, it depends on which distribution you use:
1) TeX Live 2012: Just update via Package Manager, arara is part of TeX Live 2012.
2) MikTeX: Under the assumption that MikTeX does not provide arara (I only use TeX Live) do
a) Get the installer from BinTray, under the Downloads section (at the time of this writing, the current version is 3.0)
b) Run the installer. After the installation open a command line window and type arara
If you get the following, the installation was successful:
C:\Users\Uwe>arara
__ _ _ __ __ _ _ __ __ _
/ _` | '__/ _` | '__/ _` |
| (_| | | | (_| | | | (_| |
\__,_|_| \__,_|_| \__,_|
arara 3.0 - The cool TeX automation tool
Copyright (c) 2012, Paulo Roberto Massa Cereda
All rights reserved.
usage: arara [file [--log] [--verbose] [--timeout N] [--language L] |
--help | --version]
-h,--help print the help message
-L,--language <arg> set the application language
-l,--log generate a log output
-t,--timeout <arg> set the execution timeout (in milliseconds)
-v,--verbose print the command output
-V,--version print the application version
Note that java needs to be installed, you can check with java -version on the commandline. IIRC arara adds itself to the PATH, if however you get a 'command not found' error, add arara's directory to the Windows path. More information can be found also in the arara manual
PS: I'll show arara also next week on the DANTE spring meeting in Gießen.
Best Answer
You can choose between TeX Live and MiKTeX. In practice, it does not make a difference in which distribution you use. Especially if you are new to LaTeX. However, you should take care that you install the full version, with all packages, and not a minimal or base version.
You get MiKTeX from here (choose the 'MiKTeX 2.9 Net Installer') and TeX Live here.
Both install a basic editor (TeXworks). I have the experience from my workshops with students, that they have problems with that editor. I introduced TeXstudio which worked quite well in the lectures.