Over the years, I've seen a lot of parking apps that let you drop a pin at your parking space, and then you can navigate back to the marker when it is time to return to your vehicle. iParked (free) does those apps one better, and definitely gets my "gee, I wish I'd thought of this" award for the week.
You launch iParked before you leave for your destination and will see your location on a moving map. When you come to a stop sign or a traffic light, the app drops a marker. If you start up again, marker is picked up. The app leverages your iPhone's motion tracking sensors and GPS.
I tried the app recently when I went out to lunch. iParked did drop a marker at every stop, but when I finally got out of my car to walk to the restaurant, the marker stayed with my car while a blue dot showed my current position. The app runs in the background so you can do whatever else you do with your phone and not lose your parking place.
As a nice bonus, iParked has a timer to alert you to when your parking meter will run out. iParked is a clever and welcome improvement in the current selection of parking apps. They all work well, but most make you manually drop a pin to mark your position. iParked dispenses with that, making it more useful and showing some fresh thinking.
iParked is a new app store release requiring iOS 7 or later, and it is optimized for the iPhone 5. I think you will like it, so give it a try if you often need help finding your car.