KING 5 has the story:

A Seattle man put his life on the line to save a stranger from a vicious pit bull attack. Katelynn Doolittle was jogging near Lake Washington when a pit bull got away from its owner and attacked her. She was bitten five times. Matt Loyd saw what happened and ran to help her. He blocked the dog so she could get away, getting bitten in the process. Katelynn says she's sure she would have been seriously hurt if it wasn't for Loyd.

Full thing here.