Unfortunately, no turn-by-turn, but a new free piece of navigation software still is available. It is called "Here I Am" from Arboretum Software.
It is very simple. All it does is gathering your location and then sending a link to Google Maps via email. That's basically it.
This software might be also useful to people who who simply want to record where they have been. Just send an email to yourself and there you go.
There is another point about this app. It can display the accuracy of the positional data, so maybe you want to play with it while walking about in order to get a better eye for it.
Funny thing though: there is another Application named "Here I am" available, doing exactly the same but being from another developer. Yeah, we all like the App Store....