[CentOS] backup with dd

hi all,

i have a centos box and would like to back up just in case the hard drive 
fail.  one way to do this is duplicate the image of the hard drive, so if 
the hard drive fail, just remove it and put mirrored hard drive and done.

here my system info:

uname -a
Linux jadenet.jadesterling.com 2.6.9-22.0.2.EL #1 Tue Jan 17 06:51:40 CST 
2006 i686 i686 i386 GNU/Linux

df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
                        37G   15G   20G  43% /
/dev/hda1              99M  8.9M   85M  10% /boot
none                  188M     0  188M   0% /dev/shm


i'm looking into dd, but is there anything better than dd?

by the way, i would like to use external hard drive via usb to do mirror 
image.

this is an internal box and very little info/actvities going on in this 
box.  so, i don't have to worry about backup everyday.  i may want to 
backup once a month.

thanks,
T. Hiep