I remember a relatively old film about set at an all girls school. A new girl (really into her boyfriend), with dark hair realises that her school is perfect as it is.

When there is a movement to unite the school with an all boys/ brother school this girl and her friends rebel and take the school into their own hands. They spike the drink at a social/ball in order to illustrate that the boys are not suitable.

I also remember a scene where the girls spike up their hair, put socks into their bras when the girls get ready for the above mentioned to do.

I'll appreciate any help
Thanks so much

Maybe "All I Wanna Do" with rachel leigh cook

Strike! (http://www.imdb.com/title/tt0120692/)

Thank you!

You're both right.
It is apparently also known as the hairy bird

Thanks again I can't wait to see it a second time!