The Salesforce standard lookup functionality renders a dialog that supports a small amount of customization. The fields displayed may be configured; if Enhanced Lookups has been enabled, the results can be filtered and ordered, and large result sets may be paged through. The lookup dialog's layout cannot be altered nor branded , nor can it contain additional help text.
In this recipe, we will create a Visualforce lookup page that replaces the lookup dialog and provides additional instructions to the user. An additional Visualforce page will demonstrate how this can be integrated into a custom opportunity create page.
This recipe makes use of a custom controller, so this will need to be created before the Visualforce page.