AutoUnpack is a freeware utility that can be used to automatically download,
repair, and unpack all RAR-, 7z-, zip-, TS - archives, or splitted files (e.g.
*.001). Which is especially useful for usenet binaries.

Normally people will start QuickPar while downloading (or afterwards) to verify
whether the downloaded files are complete and to repair them if necessary. Then
it is time to extract the downloaded files with WinRAR or 7-Zip . Finally they
will delete the RAR and PAR files. So a couple of actions have to be performed
by the user. AutoUnpack can automatically do this for us as follows:
1: While downloading files from usenet, start AutoUnpack and tell it which
folder it should monitor (your download folder).
2: AutoUnpack analyzes this source folder to search for PAR2 files. It uses them
to verify the downloaded files that belong to them. If some files are
incomplete or missing and there aren't enough PAR2 repair blocks available,
the program will show how many blocks are missing. It will analyze the folder
again later (10 minutes for example).
3: If enough PAR2 repair blocks are available AutoUnpack will repair the missing
or incomplete files (if necessary).
4: AutoUnpack will verify whether the repair was successful. If so, it will
unpack the archive to extract the files.
5: Finally AutoUnpack can remove the RAR and PAR files after extraction.
Easy! Just start your download and start AutoUnpack as well. If all files or if
enough PAR2 repair blocks are available, AutoUnpack will do the rest. It is able
to repair all files in a PAR2 set, including MP3 files for example. It is able
to unpack RAR archives but also splitted files ( 001 files ).
(source: binaries4all)