Two examples I can think of in children's lit that do the switching between POVs. Sharon Creech (who has won the Newbery) has done it several times, but the one I remember most is in a book called The Wanderer, in which the two POVs are necessary for the reader to have the whole picture--the characters don't understand the whole picture till the very end, so their character development depends on that POV switch. This one is done in two 1st-person narratives, and each chapter labels the character who's speaking, like EUOL said.
The other one is When My Name Was Keoko by Linda Sue Park, which tells the story of two Korean siblings, a boy and a girl, during the Japanese occupation (based on the stories of her parents, which is a fascinating story itself). Anyway, it's a little harder to deal with in this story because one character, the girl, is 1st person past tense, and the brother is 1st person present tense.
Yet it works for this story, because it helps with characterization. The brother lives in the present, while the sister seems to be telling her story from the perspective of having had time to reflect on the story. And it helps differentiate the characters, so you know if it's in present, it's Tae-Yul, and if it's in past, it's Sun-hee (though the chapters here are also labeled by speaker, too).