We have done a naming ceremony for both DC, here's a rough version of what we did, we did it at around 6 months for both of them
Hired a room somewhere (in a resteraunt for one, community centre for the other)
asked my dad to 'host' the whole thing - he's really good at speaches / public speaking etc, he welcommed everyone, explained why we were there / what a naming ceremony was (which he had to ask me!
)
We chose a couple to be the equivalent of godparents - we never did find another name that we liked, first time around we called them mentors - but they have just become godparents over the years
me / DH talked about the DC, why we chose the name etc
'godparents' make a speach - promises to DC
all grandparents were offered the chance to do the same, some did - some not
then me / dh made promises to DC, and talked of our hopes for them
second time around DD also made promises to her brother, something like I promise to let you drink your milk and share my toys! 
We had a guest book each time for people to put a message in for the DC
and this time around we also lit a chinese lantern and asked everyone to make a wish for DS as it went up. Close family were also given one to take home and do (as it wasn't quite the right weather to be doing them all)
We have always really enjoyed them, put on a bit of a spread after - everyone loves it!