Public service announcement: Prior to http://drupal.org/node/150245, hook_schema() was always defined in a module's .schema file. There was never any good reason for it to be there. The bad reason was "to avoid parsing the extra code in .install." However, the results of hook_schema() are cached so the functions only have to be called when modules are enabled/disabled or when CCK type structures change. This is very rare and parsing the .install files only on those occasions is not a performance issue. Now, hook_schema() must be defined in .install. The good reason for this is that it makes much more sense to have the schema definition and the schema update functions in the same place. It will make bugs of the "changed hook_schema() without a hook_update_N() or vice versa" sort less likely. And it is where God intended hook_schema() to be (says the atheist). If this had been an actual emergency, your mail server would already have crashed. Thanks, Barry