What do you write in a christening card?

Rose • Fiancée & Mommy

I'm going to my fiancé's colleagues christening for his 9 month old son on Sunday and we want to get a card and give them some money/a gift, however what the heck do I write in the card!?

Also what is a good gift for a christening seeing as they aren't very very close family, just work friends ?

I've never been to a christening before!