You can go to the page you want to suggest and click on "suggest page to friends," but it limits how many invitations you can send at once, so depending on the number of friends you've got (I've got over 600), you might need to send more than one suggestion message and just start where you left off.
At any rate, if you click on "suggest page to friends," it opens a box with all your friends. You have to click on each one individually (a "highlight all" feature would be great), but once you do, you can send the suggestion to all the clicked friends at once.