Manga with girl that pretends to be a boy?

Kobayashi ga Kawai Sugite Tsurai!!

Sarasah

Romeo x Juliet

Danshi ing Girl!

Tomodachi Kara Yoroshiku Desu

Ningyo no Ouji-sama

Mousou Samurai Kareshi

Love Zipper (collection of oneshots, first chapter's main character is a boyish girl who's popular with girls)

Oh, and if you wouldn't mind, you should also check out Pretty Face. It's an interesting and fun manga about a boy with a girl's face after the surgery he got after he was in a bus accident.

He Dedicated to Roses

Idol Shopping

Nice Guy Syndrome

Boy of the Female Wolf

Love in the Mask

My Boyfriend is a Vampire

Love Sick

Hana No Kishi

Boku ni Natta Watashi

Tokyo Crazy Paradise

Oran Highschool Host club

Love sick

Tokyo Crazy Paradise

Princess Princess (boys dress up as girls)

Hana No Kishi

You pretty much just described "Seiyuu Ka". It s a manga about a girl who attends an art school. In the story, she is taking classes to try and become a voice actress that is "cute", but when ever she tries to sound cute, her voice gets all raspy. One day, in a moment of dire importance, she has to voice act for something and her voice sounds like a prince. Because of this she gets recruited to a company. The catch is, she has to dress and act like a boy, because they recruited her for her manly voice.

This was a really great story and I would recommend it. There is a romance in there, but it may slightly anger you : ). Even then, I think you'd like it.

Nisekoi - is a good one the lead character is a boy but there is a girl character in it that pretends to be a boy she's pretty cool and a good fighter, it a great anime full of laughs I was almost crying in some bits haha and of course there is some cute romance in it but definitely worth watching :)

and also...

Your questions made me think of an anime called Infinite Stratos it's a pretty good anime with 2 seasons, it's a robot type mecha one. The lead character is a boy but there is a also a pretty cool girl character that pretends to be a boy. the scene when she is first dicovered to be a boy is priceless >.< hahah

theres fighting and stuff which is pretty cool and also a bit of romance another great funny anime I highly recommend to watch

Hope this helps :D

Ouran High School Host Club

Hana Kimi

Power!

Love in the mask

maid sama is kind of like that. The storyline is about a girl who attends a former all boys school. The girls are a small minority. She works her way up to becoming student council president. She is tough, and rough with the boys. Always willing to knock them out. And she eventually meets a special someone.

Gekkan shoujo nozaki-kun, although the lead female character does not dress or pretend to be a boy, one of the main characters does. Sorry it doesn't fully fit with your description, but i think you'll really like this one! its hilarious :D

Ouran highschool host club is the only anime I know that a woman pretends to be a man.