K.P.
I've only attended one, but it reminded me quite a bit of a Baptism. They rabbi will pray for the child and her parents and will ask the parents what name they would like to give her. It's a very meaningful and pretty ceremony.
We gave a check for $50 and a small piece of jewelry. Most people did something similar. Some did large checks and no jewelry. Some did jewelry and no check, but those were the most common gifts. Again, very similar to a Baptism or Christening!