The subject of 'table manners' is interesting because behavior that is considered rude in one culture may actually be the polite thing to do in another. Burping is the perfect example and one that comes to mind because I had a conversation about it today. In most Western cultures, this is rude and definitely regarded as disgusting. I'm usually OK with it but I did find it a little gross when we were surrounded by it during meals out in Indonesia. Although, after awhile, I hardly noticed it. A quick check through Google seems to show that some Eskimo tribes and South Sea Island tribes burp as a sign of politeness at the end of a meal.
I also came across this fun site for kids. Its in the form of a quiz about the table manners from different countries. Give it a go here.
And if you want to do even more reading on this, here are a few from Gimundo.com