Comments - terkhen

You can find OpenTTD download in its homepage: Openttd.org

Check this post to see a discussion about this in the forums: Tt-forums.net

If you mean the graphics, some of the screenshots currently being shown here are taken with the original Transport Tycoon Deluxe graphics files. Although OpenTTD supports them, by default it uses open source graphics (called OpenGFX). If you want to use the old graphics you need to own Transport Tycoon Deluxe and to follow the procedure described in section 4.1.2 of the readme.