How to backup my MacBook (10.4.11)

Hi, I finally got an external harddisk (WD pasport 250GB) to backup my (80gb) harddisk of my macbook (Tiger version), but since i am absolutely new to this and a lot of the info is old online, I decided to ask here. I have no idea how to do this right. I am not a techie, so easy does it for me. I downloaded Ibackup, but it looks complicated and does not seem to work either.
Any tips, ideas, suggestions are very welcome. Also urls or links to recent useful sites or explanations. Preferably 'free' or inexpensive solutions for the moment for my purse please.
Thanks

;D

Super Duper works great. we use it here at work to back up each workstation's systems. it basically makes a mirror of your entire computer. so if even if your OS goes out, you can start up from your external and work just like you never lost anything.

http://www.shirt-pocket.com/SuperDuper/SuperDuperDescription.html

Did I buy the wrong harddisk

Hi, thanks for your reply to my post. i downloaded superduper and reading the instructions I just found out for superduper i need a firewire harddisk and i just bought a USB 2 Western Digital passport disk... It really can't be done with USB? Which harddisk are you using?