My son gets bullied at times too and he is just six. I actually borrowed a book from the library on how to deal with it. I am basically trying to teach him to stick up for himself, and say things in a strong tone of voice and with confidence. Not an easy thing to teach a six year old! But, I often do it with toys in certain situations. I agree, approaching the school. They should have an anti-bullying policy and I also think scheduling a "meeting" with the school, and the other parent's is a good idea...so that everyone is aware. Isn't it crazy how mean kids are?! I was bullied a bit too, well, OK, it was alot. So, I will be dam*ed if I let it happen to my kids!

In my personal experience of girls getting into bitchy arguments at school, and also from seeing somethings my sister and her friends have been through, i would strongly advise NOT to approach the mother.
You will probably not be met with the what should i do attitude, but more the how dare you insult me my child or my parenting skills attitude. She would take it personally and she would probably say something hurtfull to you about your child.
I would talk to her teacher at school, headmistress or year leader. They can monitor it from inside the school and if they see this other girl acting... they can contact the parent as an eye witness of bullying going on. That way the mother will probably be more obliged to help and be more sympathetic.
But also as the others have said make sure your daughter can come to you and tell you whats going on, if she bottles it up it will only cause more damage. Teach her to stick up for herself, but not too much and not vilently, teach her how to be classy about it, one word answers and walking away. etc, She will feel proud of herself if she learns to stand up to them without being confrontational.
Hope it gets sorted out soon.

personally, I would approach the parents first. It shames me to say this, but when I was about 6/7 I started bullying my best friend. After a while, she obviously told her parents who came up and told my parents. It was sorted out there and then, and I never bullied her again. Parents can strike the fear of god into their kids' hearts! If this doesn't work or the parents are in denial, hit the school!

that sound so much like me! i was very shy at infants/primary i didnt have very many friends and when we had to pair up for PE or anything i was always the one left one my own and ended up with the teacher.
I want my kid to be confident and aout going not like i was are still am.
bullying has made me very unconfindent, and nervous.
i hope they never have to go through it.

I would speak to the school, i certainly wouldnt confront the parents it could make things worse at least the school can keep an eye on things.