Userscripts.org

Love the script. Here's a modified version with a few changes that allows for URLs that don't just stick the title on the end (my library seems to care about the order of the request variables, which is totally ridiculous), and that allows you to search by ISBN13 if your library lets you (more accurate than a title search). You can still use it for just title searches by putting {{title}} in your base_url, this is just a little more flexible.

Here goes:

// ==UserScript==
// @name Goodreads ISBN/Title Library Search
// @namespace http://yonisamlan.com
// @include http://www.goodreads.com/book/show/*
// ==/UserScript==

//To use your own library here, just replace the library_name and base_url with ones that match yours.
//In the url, use {{title}} or {{isbn13}} to use those items in the search URL.

var library_name = "Minuteman Library"; //Eastern MA
var base_url = 'http://library.minlib.net/search/i?SEARCH={{isb...;

var title = document.getElementById('bookPageTitle').innerHTML;
var isbn13 = document.body.innerHTML.match(/isbn13: [\dX]{13}/)[0].replace("isbn13: ","");

var search_url = base_url.replace("{{isbn13}}",isbn13).replace("{{title}}",title);

var linksDiv = document.getElementById('affiliateLinks');

var full = document.createElement('span');
full.setAttribute('style', 'font-weight:bold');

var txtNode = document.createTextNode(library_name);
var link = document.createElement('a');
link.setAttribute('href', search_url);
link.setAttribute('target', '_blank');
link.appendChild(txtNode);

full.appendChild(document.createTextNode(' '));
full.appendChild(link);
full.appendChild(document.createTextNode(' | '));

linksDiv.insertBefore(full,linksDiv.childNodes[3]);