slagg

Who knows a manga that the theme is "high school"

I don't read manga =P. But some good anime that you can probably get in manga style are: School Rumble, Cross Game, Shana, and you should know Toradora and Lucky Star, and pretty much any other anime in existence. (I am guessing you are looking for uniforms so you can draw them? Try going to a picture site and searching up uniforms. You can try places like http://safebooru.donmai.us/ which seems to be down atm, or http://gelbooru.com/ and search up uniforms and make it a safe search)

I kinda read manga alot, so I could recommend you some, but I'm not sure what you're after?

High School is the setting for MOST shounen/shoujo titles, and even some more mature series are set in, or have characters in high school.

If you want something thats kinda slice-of-life in highschool, then stuff like Azumanga Daioh and Lucky Star is the stuff to read, although both of those are 4koma =p

Also: @Wej, you dont read manga!? How do you get your loli fixes? Try authors like inuboshi, gorgeous takarada, LEE, Naoshi Onizuka and Hoshino Fuuta. Faptastic goodness.

I do read doujinshi and things like that, but not normal manga. I am going to try to start reading them in Japanese though =D. Most manga for a younger audience have furigana in them so I can actually read them. I have a random 5 volume series manga with cute as fuck loli in them.