Otome wa Boku ni Koishiteru revolves around the lives of a group of friends at Seio Girls School and their interactions with each other after the main protagonist, Mizuho Miyanokouji, transfers to the school. Mizuho is a nice person with morals who was born in a good and loving family, but after his grandfather passes away and his last will in testament is reviewed, it is discovered that it was his desire to have his grandson transfer to an all-girl's school - the same one his own mother attended and his ancestors founded. Abiding by the will, Mizuho crossdresses in order to attend the school as a female.
it's a short (12 ep only!) anime but really nice.
my favorite part of this anime is...
well, it's not really a part of the whole story but it's a short story using the otoboku characters...
it's an OVA...
and it's entitled, "tsunderella", i think?
watch fan-made opening: