When D&D 3.5 was announced (see 'Wizards of the Coast Goes Beyond 3rd Edition'), Wizards of the Coast promised that it would be backward-compatible with 3.0 publications; now it's announced how.  In conjunction with the new version's July release, WotC will offer a backward-compatibility guide that players will be able to download.  The guide will allow players to use their existing D&D accessory titles with the new core rulebooks, and also includes revision notes for the Epic Level Handbook, Fiend Folio, Manuel of the Planes, Deities and Demigods, and Monster Manual II.  The upgrade also contains general advice for use with any D&D 3E supplement.