If you don't have the textbook yet, here are some of the early readings:
Plato: The Cave
Descartes (Meditation I) Descartes
(Meditation II): Descartes
The Locke reading in the book is a composite of snippets from a large book, An Essay Concerning Human Understanding. The following links are the best I could do to get you roughly equivalent material:
Locke (Essay II, Chapter i, sections 1-10, 23-25; Chapter ii; Chapter vii, sections 7-17)
Locke (Essay IV, Chapter ii, sections 1-14; Chapter iii, sections 1-7, 21 and 31)
The following is a good summary of the positions of the Presocratics, but does not have the primary source material assigned from the text book: Presocratics
(2nd Reading - chapter 7)
Phil-6: Stace reading, quiz!
Phil-26: Locke Reading, quiz!
Phil-103: Johnson, chapters 1 and 3.
Phil-300: Johnson reading, quiz!
Hist-308: Chapters 27 and 28, Connect system work.
Chapter 9, keep reading the Inferno.
Some of my favorites will appear below: