Facebook Lightbox Premium is a wordpress plugin that displays a lightbox when people visit your webpage, that looks similar to a popup window, but isn’t blocked by popup blockers.
This plugin enables you to get more Facebook fan page likes from visitors to your website. If you have a high traffic blog, this will enable you to grow your Facebook fans significantly.
The plugin is configurable so that visitors will only be asked once per day, per week, or per month if they wish to like your page.
Visitors will also see their friends faces who have already liked the page, so this helps with social proof of your company, brand, or product automatically.
The premium version also has the option not to display if visitors have already liked your page.
Available from Arevico (click here to visit site).