Growing up I was a girl who liked sports, hated skirts and was always hanging around her brother and his friends. Sometimes it even went so far that I would only wear my brother's clothes. For all the little girls that do this, we are labeled "tomboy" and no one thinks twice about that label.
In our society, most things are assigned a gender and there is usually an equivalent for the other gender. I found it interesting that this general rule did not apply to the idea of being a tomboy.
Maybe I was wrong and there was a boy version of tomboy that I was just unaware of. So I did a little research and found that there is no word describing a boy who acts feminine. Some of the responses I did see were, "gay", "nancy" and "metrosexual." Metrosexual is definitely not the word people are using because I've never once heard someone call an eight year old metrosexual. That just sounds ridiculous. The more common terms seem to be "gay" or "nancy." It's interesting to see how boys showing femininity is a problem, but girls showing masculinity is encouraged.
Our generation is starting to question gender roles and what it means to live as a woman or a man. Being feminine isn't seen as such a bad thing anymore. There is nothing wrong with a girl playing football and there is nothing wrong with a boy dressing up as a princess.
So don't worry about the labels because in the end, they don't really matter. Just do what makes you happy.