If people are driving instead of flying this summer for a holiday across Europe, this app could be useful for you. Downloaded through iTunes for £2.99 you can gets maps for France, Germany, Spain and the Netherlands. I have the UK app as well through iTunes which is also very good, better than Google Maps that comes with the iPhone anyway!
I couldn't get the link to work from iTunes but if you type in Navmii it will come up - you want Navmii GPS Live for Europe. The website's worth a look as well because the UK maps are compatiable with other handsets not just the iPhone.