References to other site everywhere in WordPress site

There might be hardcoded links in the theme; download it and do a multifile search with a text editor.

Editing the text dump destroys serialized data; see another Q/A here: Why is my database import losing text widget data?

Update 4/19/2015 To correctly change URLs in the database, the SQL queries below will work when run in phpmyadmin or adminer, but it is much better to use a tool that correctly deserializes/reserializes php data, like https://interconnectit.com/products/search-and-replace-for-wordpress-databases/

UPDATE wp_options SET option_value = replace(option_value, 'http://olddomain.com', 'http://newdomain.com') WHERE option_name="home" OR option_name="siteurl";

UPDATE wp_posts SET guid = replace(guid, 'http://olddomain.com','http://newdomain.com');

UPDATE wp_posts SET post_content = replace(post_content, 'http://olddomain.com', 'http://newdomain.com');

UPDATE wp_postmeta SET meta_value = replace(meta_value, 'http://olddomain.com', 'http://newdomain.com');