Viva Bahrain has just launched "free Facebook" aka Facebook Zero to its customers. If you have a phone with data access (data bundles not necessary) and a mobile browser you can access Facebook Zero through one of the following addresses:
You get a basic Facebook interface suitable for mobile phones (much like m.facebook.com) and you will be allowed to access most of Facebook's services (updates, feeds, messages etc…). You will be charged if you decide to open a photo or click on a link that leads to an external page (any link taking you away from Facebook). Also note that due to the nature of SSL, if you add https:// to one of the URLs above you will be charged even though it is a Zero URL.
If you do end up doing something that will get you charged, the data fees are very affordable: BD0.002/100KB (Prepaid) or BD0.003/200KB (Postpaid). Alternatively you can add a data bundle to your account.