If your venue is fairly remote then it may be a good idea to hire a taxi company for the evening to take the guests back to their accommodation at the end of the night, or at the very least let the local cab firms know that there is a wedding going on so that they know where to pick up slightly inebriated and disoriented out-of-town guests when they phone for a taxi! This is an especially good idea if you have a lot of out of town guests as they will not be aware of the best companies to hire, or where exactly the wedding venue is. You may also be able to reduce the cost of the taxi hire if you hire them out in bulk. Beware though, it may add considerably to your wedding costs as taxis are quite expensive. If you are using a large venue then they may have a taxi company that they usually use and are able to recommend. The taxi price usually goes up at midnight so bear this in mind when scheduling the end of your wedding reception as you may find guests are keen to leave at 11.45pm if they are relying on a taxi cab to get them home.
For London weddings it is so much easier as black cabs are readily available late at night, some of the larger wedding venues have their own taxi rank and otherwise can order taxis for your guests when they know the wedding reception is due to finish.