A Brief History of Life
NOVAs Origins program offers an interactive evolutionary timelines. Take a stroll from the Precambrian to the Quaternary.
Timeline of Evolution
Wikipedia offers a timeline highlighting the emergence of different species over the last 4000 million years.
Steve Rose's Evolution Timeline
Offers a proportioned -- 1 inch = about 2 million years -- evolutionary time line tracing life from first its very first forms to homo sapiens.
PBS Evolution offers an interactive timeline to help readers better understand geologic time and evolutionary change.