You can always use a custom Facebook Like Button that displayes the number of likes from the FB Developer’s page. But if you’re looking to control the way that number is displayed (maybe a large font or in a funky graphic), you can access this information using the Facebook Graph API URL. It will return all the Page information in a JSON data format like so using Pepsi’s Page:
http://graph.facebook.com/56381779049
The number 56381779049 could be the Page or User ID you’re referring to on Facebook. Notice how it will return a array of information. You will find that total number on the line labeled “likes”.
Fantastic advice
And I’ve written a script which can help you out:
http://www.andy-howard.com/numberOfFacebookLikes/index.html