Create a backup directory for storing the scheduled SharePoint backups (e.g. c:\backupsharepoint)
Create Bat File Directory
Create a directory for storing the backup script file (e.g. c:\scriptssharepoint)
Create Bat File
Create a bat file using the code below, modified for your environment. Use UNC paths when using in a server farm environment.
echo Backup Script For Office SharePoint Server 2007
cd \program files\common files\microsoft shared\web server extensions\12\bin
stsadm.exe -o backup -url http://servername -filename c:\backupssharepoint\backupsharepoint.dat -overwrite
Schedule bat file
Schedule the backup to run frequently, during off peak hours.
Open Start > Programs > Accessories > System Tools > Scheduled Tasks
Add a Scheduled Task
Scheduled Task Welcome Screen, Click Next
Click the program you want Windows to run, Click Browse
Select the backupsharepoint.bat file you created (e.g. c:\scriptssharepoint\backupsharepoint.bat)
Name the task, Schedule it (e.g. Daily)
Start Time, Frequency, Start Date
Username and Password (use a domain user account that has proper permissions and non expiring password )
Keep the backup directory secure. Monitor the job to ensure the job is running properly. Perform test restores from the backup files.