This has got to be one of the easiest replacements you can do on a car. Tools are not required! Quality!... Here's a rough step-by-step guide on how it's done!
1) Open the bonnet, and remove the cap from the back of the headlight.
2) Pull off the cable block (the wires attached to the bulb). These are not clipped on, and come off easily!
3) There are some retaining clips which hold the bulb in. Unclip these!
4) The bulb should now be loose inside the headlamp.
5) Make a note of the way the bulb was removed as they only go back in one way!. Remove the bulb!
6) Get the new bulbs BUT DONT TOUCH THE GLASS PART OF THE BULB!
7) Put the bulb into the headlamp (right way up) and re-fix the retaining clips
8) Attach the wires back to the bulb! They only connect one way, so you cant get this wrong!
9) Replace cap and test the lights.