I have built a WordPress site and theme and have several pages that I do not want editors to edit. However, there are other pages that I want them to have access to to edit. Is there a plugin or code that will lock certain pages from being edited by anyone other than the admin?
Have a look at the Members Plugin by Justin Tadlock.
It has a "content permissions" feature, that let's you restrict posts and pages by user role.
Alternatively, if you wanted to implement this yourself, you could write a shortcode that redirects the user conditionally. And place that on pages you want to restrict.
Since there is an excellent and well written plugin for this job however, this is one of the few occasions where I'd recommend using an existing plugin over coding it yourself.
Along the same lines of Members plugin and Role Scoper, I like User Role Editor - http://wordpress.org/extend/plugins/user-role-editor/ It is the most simple to use of the user role editors, in my opinion and a big plus... The developer is always around to assist and take feedback. I'm not saying the other's are not. I just know from experience the User Role Editor developers are always willing to lend a hand.