Many iphone apps are location aware, and use "check in" type functions. Typically these are used to "rate" hotels and eating establishments. eg "FourSquare". The tourist and service industries should take special note of this new movement in networked smart phone technology.
FourSquare tip: Get 25 people with iphones and that App to "bomb" your establishment one night and earn a badge of honor, and gain special visibility to new tourists looking for somewhere to sleep or eat..
In order to make use of Iphone Apps, you need to perhaps get an iphone app or borrow a friends to learn about how these types of apps work. When i was in San Francisco, i tried out an App to discover that many people were usign the same App in the same hotel at the same time, then imagine all the previous and future guests of the same hotel. They had also made reviews about all the restaurants within 20 meters of the hotel.
So the trick in each country will be to work out which the most popular "social networking iphone apps" are, and then ensure that they all leave positive messages for you, or at least you encourage them to.
Try this, next time someone comes to visit, and you see them using an Iphone. Ask them if they have ever heard of "FourSquare", if not, suggest they install it just for a laugh. It is free. Then ask them to check in, and have a little look around the app together to see what interesting things you learn. Even if there is not much info there, at least it is a start, and you have one up on the next smart tourist who travels via their iphone travel suggestions. Note you may need to provide your guests with wireless access. I think it is a good idea to provide free wireless access to your guests as a feature provided free with the room cost. Providing free internet is much easier to manage that one that has pricing for usage. Your guests will also find it easier to use, and will love you for it. It will give you a point of difference over other accommodation providers in your town.
Notes abour privacy - It really is quite easy to use these apps, and although you are letting the network know that you are here, it is not really much different that swiping your credit card, or acting loud and obnoxious after too many drinks... The point of these applications are really about better travel guides, and so best we think about it that way. By providing these free apps, the makers are using "crowd sourcing" techniques to gather fantastic timely and relevant industry knowledge. It is a win win for all involved.