Miley Cyrus' autograph just became that much more valuable. The Hannah Montana star has signed on with Sharpie and City of Hope for the "Inking in Pink" campaign to raise funds for breast-cancer research. For the month of October, Cyrus will sign autographs with a pink Sharpie, and for each signature uploaded to SharpieUncapped, the company will donate $1 to City of Angels. See Miley explain it all in the video below. Autograph hounds, start your hunting—and help out a good cause in the process...