I have previously talked about enable custom field search in Wordpress, but that involved altering the main Wordpress files, which is a big no-no.
So is there an alternative? Well, yes, otherwise I wouldn't have bothered writing the post! To enable custom field (also called Wordpress metadata) searching you need to set up two things.
First you need to have created a custom field (or two) and added this to a number of posts.
Next, you need to have a custom search form that has the name of the field set as the name of an input box. You don't even need the normal s input box that Wordpress uses as default.
Open up your template functions.php file and add in the following three lines of code.