Any advice on how to take good photos at a christening?

I'm attending a family christening tomorrow and have been asked to be the photographer for the day. The thing is, I'm much more used to taking pictures of buildings and landscapes and have not had much experience photographing at events. I have decided I'm going to use a Nikon D40 camera, which has an 18-55 mm lens. I want to get some interesting shots that will be treasured and help people to remember a lovely day, it would be great if anybody could offer me some advice as to how I should go about doing this.

I'd bang-box it, with flash on camera, unless you have studio lights and backgrounds. Then you want to have lots of shots of proud Momma and Poppa (and grandparents, etc.) tenderly holding and admiring this tiny new person. You can show the little head in Daddy's big, strong hands, or rig a sling from a rod held on either side by Mom and Dad of soft, white cloth just above the floor, with the baby lying asleep in the bottom, then get down low to baby's level and crop in close.

Your problems going to be the light, or the lack of it. Use a flash, preferably off camera and preferably in a soft-box.

A picture of the babies hand holding onto Grandads or Grandma's finger, old and wrinkled skin against new skin gets 'em every time.

As always shoot in Raw, you can just do so much more with them.