The parking meter is some streets of Dublin are an interesting example of an interface following the basic idea of physical mobile interaction. As you see from the manual sticker – the first part is on the mobile phone: you call a number and then provide the place in which you are (by typing in a number). The second part is then on the ticket machine – till you get the print out. The amazing thing was I really saw people using it!
The user interface design is interesting as they use on the phone typical phone interaction (basically dialing an number) and keep the interaction with the ticket machine the same (except there is no need to insert coins) as it was before. But looking at some work we did in the PERCI project with DoCoMo in Munich we can tell that this is just the initial state of physical mobile interaction  – it can be expected that this will become more common!
 Broll, G., Siorpaes, S., Rukzio, E., Paolucci, M., Hamard, J., Wagner, M., and Schmidt, A. 2007. Supporting Mobile Service Usage through Physical Mobile Interaction. In Proceedings of the Fifth IEEE international Conference on Pervasive Computing and Communications (March 19 – 23, 2007). PERCOM. IEEE Computer Society, Washington, DC, 262-271. DOI= http://dx.doi.org/10.1109/PERCOM.2007.35