[Link14716]

Run these queries:
[sql]DELETE FROM phrasetype WHERE phrasetypeid='716';
DELETE FROM phrase WHERE varname LIKE '%shoutbox%';
DELETE FROM setting WHERE varname LIKE 'shoutbox%';
DELETE FROM settinggroup WHERE grouptitle='shoutbox';
ALTER TABLE language DROP phrasegroup_shoutbox;
ALTER TABLE usergroup DROP shoutboxpermissions, DROP shouthierarchy, DROP shoutmaxdaily;
ALTER TABLE user DROP shouts, DROP shoutbanned;
DROP TABLE shoutbox_posts;[/sql]

EDIT: Well, even if you use uninstall.sql, you'll need to run this since I haven't updated unsinstall.sql since Beta 5.
[sql]ALTER TABLE usergroup DROP shoutmaxdaily;[/sql]