How To Tar

compressing: www/ directory:
tar -pczf filename.tar.gz www/

How To UnTar

untaring filename.tar.gz
tar xvfz filename.tar.gz

Thats it, that the most simple way i can show you.

hope this helps
       tar - The GNU version of the tar archiving utility

       tar <operation> [options]

       [-]A --catenate --concatenate
       [-]c --create
       [-]d --diff --compare
       [-]r --append
       [-]t --list
       [-]u --update
       [-]x --extract --get

       Common Options:
       -C, --directory DIR
       -f, --file F
       -j, --bzip2
       -p, --preserve-permissions
       -v, --verbose
       -z, --gzip
       This manual page documents the GNU version of tar, an archiving program designed  to
       store  and  extract files from an archive file known as a tarfile.  A tarfile may be
       made on a tape drive, however, it is also common to write  a  tarfile  to  a  normal
       file.  The first argument to tar must be one of the options Acdrtux, followed by any
       optional functions.  The final arguments to tar are the names of the files or direc-
       tories  which  should  be archived.  The use of a directory name always implies that
       the subdirectories below should be included in the archive.

       tar -xvf foo.tar
              verbosely extract foo.tar

       tar -xzf foo.tar.gz
              extract gzipped foo.tar.gz

       tar -cjf foo.tar.bz2 bar/
              create bzipped tar archive of the directory bar called foo.tar.bz2

       tar -xjf foo.tar.bz2 -C bar/
              extract bzipped foo.tar.bz2 after changing directory to bar

       tar -xzf foo.tar.gz blah.txt
              extract the file blah.txt from foo.tar.gz

       One of the following options must be used:

       -A, --catenate, --concatenate
              append tar files to an archive

       -c, --create
              create a new archive

       -d, --diff, --compare
              find differences between archive and file system

       -r, --append
              append files to the end of an archive

       -t, --list
              list the contents of an archive

       -u, --update
              only append files that are newer than the existing in archive

       -x, --extract, --get
              extract files from an archive

              delete from the archive (not for use on mag tapes!)
       -C, --directory DIR
              change to directory DIR

       -f, --file [HOSTNAME:]F
              use archive file or device F (default "-", meaning stdin/stdout)

       -j, --bzip2
              filter archive through bzip2, use to decompress .bz2 files

       -p, --preserve-permissions
              extract all protection information

       -v, --verbose
              verbosely list files processed

       -z, --gzip, --ungzip
              filter the archive through gzip

              don't change access times on dumped files

       -b, --blocking-factor N
              block size of Nx512 bytes (default N=20)

       -B, --read-full-blocks
              reblock as we read (for reading 4.2BSD pipes)

       --backup BACKUP-TYPE
              backup files instead of deleting them using BACKUP-TYPE simple or numbered

              block the output of compression program for tapes

       -C, --directory DIR
              change to directory DIR

              warn if number of hard links to the file on the filesystem mismatch the  num-
              ber of links recorded in the archive

              print directory names while reading the archive

       -f, --file [HOSTNAME:]F
              use archive file or device F (default "-", meaning stdin/stdout)

       -F, --info-script F --new-volume-script F
              run script at end of each tape (implies --multi-volume)