Front end user creation form! How do you keep the user on the same page in event of error?

Hook into registration_errors (The WP Codex is woefully incomplete on this, but see links below). Sorry this isn’t more helpful — the issue is a little more complex than it seems at the outset. I’ll look into it more later. Links: http://adambrown.info/p/wp_hooks/hook/registration_errors http://core.trac.wordpress.org/ticket/10672 http://codex.wordpress.org/Plugin_API/Filter_Reference/registration_errors and http://codex.wordpress.org/Plugin_API/Action_Reference/register_post

Can I change default registration link (without htaccess)?

If you want to keep this information in the $_GET, you will have to modify the form’s action parameter URL. You can do this by hooking into site_url: add_filter( ‘site_url’, ‘wpse18418_site_url’, 10, 4 ); function wpse18418_site_url( $url, $path, $scheme, $blog_id ) { if ( ‘login_post’ == $scheme ) { $url .= ‘&role=doctor’; // Or do … Read more

Data sanitization for user registration and user login

You can check my tutorial for front-end user registration and login in WordPress: http://www.cozmoslabs.com/1012-wordpress-user-registration-template-and-custom-user-profile-fields/ As to the wp_signon, wp_insert_user, wp_create_user and wp_update_user they take care of all sanitation and validation of your content. Also you don’t need to use those filters in wp_create_user to create your users.