Editing options pages?

I just did some searching and found this in the codex:

add_settings_field( 'myprefix_setting-id', 'This is the setting title', 'myprefix_setting_callback_function', 'general', 'myprefix_settings-section-name', array( 'label_for' => 'myprefix_setting-id' ) );

Here is the link to the codex http://codex.wordpress.org/Function_Reference/add_settings_field

Looks as simple as choosing the right slug like ‘general’ to add an option to the general settings page.

I hope this points you in the right direction.