Drush, my favorite new tool, is proving to be quite useful.  Drush saves you time by picking up your connection string from the sites settings.php folder that you're backing up, you no longer need to configure each backup script individually. 

sample usage for this script would be:

bash backup.sh /full/path/to/drupal/site <optional> archive_prefix <optional> #of days to keep archives for

That's it!  You do need to configure the script to your servers paths for where you want the backups to be stored, and where drush is located.

Here's the command I'm calling for my cron jobs

bash /home/user/workspace/utils/backup.sh /home/user/www/site site_name 4

#!/bin/bash
# 
# Copyright (c) 2009 Chrishunters.com
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# ---------------------------------------------------------------------
#
# Version 1 - Dec 31 2009
# Drupal backup w/Drush
#
# This script was designed to backup a drupal sites files and database into 
# one gz archive.  This can be run as a cron script.  
# Sample usage: 
# bash /home/user/workspace/utils/backup.sh /home/user/www/site site_name 4
#
# pos 1: the full path to the drupal site you're backing up
# pos 2: optional name of site
# pos 3: optional override for number of days to keep old backup archives, 


#!/bin/bash
## Drush based drupal backup script

#Global Vars
basepath="/home/user" #no trailing slash here
scriptdirectory="$basepath/workspace/utils"
backupdir="$basepath/workspace/utils/backups"
drushpath="/var/drush" #no trailing slash here 

#App vars
drushsuccess="Successful"
sitename=""
days_to_keep=7

############
# Utility function to run a script and search for a particular string
# Return 0 for false, 1 for true
####### # #
bln_runAndReadOutput () {  
  script_contents=( $($1) ) 
  for element in $(seq 0 $((${#script_contents[@]} - 1)))
    do              
    	if [ "${script_contents[$element]}" = $2 ]; then
	   		#if we find the string we want, return 1
			return 1
    	fi
  done
  #if not, return 0
  return 0
}

#make sure we've got an argument for the drupal site path
if [ $1 ]; then
 echo "Checking $1" 
else
 echo "Usage: backup.sh path/to/drupal/site <optional> name_of_archive <optional> #of days to keep old log files for"
 exit
fi

#see if the directory exists                                                                                                                                  
if [  -d "$1"  ]; then
  echo "$1 is a directory, checking drupal now"
  #run and capture output into variable
  bln_runAndReadOutput "bash $drushpath/drush -r $1 st" "$drushsuccess"
  result=$?
  if [ $result -eq 1 ]; then
    echo "Found drupal site. Success."
	else
	echo "Drush could not find the site. exiting."
	exit
	fi
else
  echo "Please add an argument of the drupal install path, ie: backup ~/www/pbj"
  exit;
fi

if [ $2 ]; then
  sitename="$2"
  echo "Name was supplied as argument $2"
else #no name was specified, use the drupal site folder name

#vars
  declare -a site
  site=( `echo $1 | tr -s '/' ' '` )
  declare -i arr_length=${#site[@]} 
  sitename=${site[$arr_length-1]}
fi

#if we want to keep more or less backups for this site, 
#we can use the 3rd parameter to do so
if [ $3 ]; then
  days_to_keep=$3
  echo "Now keeping $3 days of logs"
fi

#tempdir is a combination of the scriptsdir and the current sitename
tempdir="$scriptdirectory/backup_$sitename"

#see if the site argument exists, then check to see if backup sub directory exists                                                                      
if [ -d $backupdir ]; then
 echo "backup directory found. [ $backupdir ]"
else
  echo "backup directory not found, creating now... [ $backupdir ]"
  mkdir $backupdir
fi

echo "Backing up $sitename"
if [ -d "$backupdir/$sitename" ]; then
 echo "Backup subdir found."
else
 echo "Creating $backupdir/$sitename" 
 mkdir $backupdir/$sitename
fi

mkdir $tempdir

#Use drush to get the database
$drushpath/drush -r $1 sql dump > $tempdir/data.sql

#tar/gz the files from the arg 1
echo "running: tar -pczf $tempdir/files.tgz $1"
tar -pczf $tempdir/files.tgz $1

echo "running: tar -pczf $backupdir/$sitename/$sitename_backup_$(date +%Y%m%d).tar.gz $tempdir"
tar -pczf $backupdir/$sitename/$sitename.backup_$(date +%Y%m%d%H%M).tar.gz $tempdir

#remove temp
echo "cleaning up $tempdir"
rm -rf $tempdir

#remove old files, older than 30 days
echo "Deleting old archives from $backupdir/$sitename"
find $backupdir/$sitename -type f -mtime +$days_to_keep -exec rm {} \;