This post will be updated as necessary, with a running errata document updated as necessary until the release of Alpha 2 or Beta 1.

You can download the files individually through the links below, or the entire collection as a single ZIP archive.

Overview and Administrative
License
README
Basics
Design Notes
Sample Builds

Characters
Character Creation and Advancement
Races
Base Classes
Prestige Classes
Bloodlines
Racial Paragon Classes
Feats
Skills

Equipment and Magic Items
Equipment
Magic Items

Magic
Spell Lists and Domains
Spells

Referee's Handbook
For Referees
Bestiary
Combat
Playing Beyond 20th Level
Adaption Guidelines

Accumulated Errata
Errata (as of 28 Sep 2010)

For those who've asked, I've put the content above into three main documents:

Player Guide: Basics, character creation and advancement, races, base classes, prestige classes, bloodlines, paragons, feats, skills, and equipment.

Magic Guide: Spell lists and domains, spells, and magic items.

Referee Guide: Referee info (adaptation, experience, etc.), combat, special abilities, types/subtypes, bestiary, playing beyond 20th level, and adapting 3rd party material.

A fourth document "Release Notes" includes the release notes and design notes.

This grouping of subdocuments hasn't been thoroughly reviewed, so take it for what it's worth. The content should be the same, but layout may be different.

The same errata (as of 28 Sep 2010) applies.