I am absolutely for women breastfeeding in public. It is a ridiculous argument to suggest that they can't.
However, I think that standard guidelines should apply.
1. If the baby is not allowed to have a bottle (like on the bus) they cannot breastfeed.
2. Cover up out of respect. Some people are uncomfortable with a woman's nipple. I don't get why, but they are. I have nursed in public places and no one had any idea I was because I was covered up.
3. If they ask you to leave for breastfeeding, stop feeding your screaming baby and proceed to stand there until they ask you to leave for having a screaming baby.
4. Bring a pacifier or toy to distract the baby until you can get some place where people aren't so uptight about the human body.
One of my friends said this the other day:
"It's only guys that are upset about breastfeeding in public... and it's because they are mad they can't have any and they have to be reminded of that...."
Not sure if it's true... but it sure was funny at the time.