Try out the Avenza Maps app. You can get it for both iPhone and android. You can download the free USGS quad map for your area into the app and then place pins as you walk or turn on tracks and walk your roads.
Then you can export those features in KML format which is readable by google earth.
You also might just beagle to use google earth on your computer with aerial views to see you roads and map them that way.
I tried Avenza but was not able to get it to work. I am not so good at this. I´ll try again, maybe with the help of a kid.
I also tried Map my walk. Had a little more luck with it but Avenza has features which should prove more useful--if I can get it to work. "Map my walk" let me show the path I walked but I had to get very inventive to show forks, dead ends, etc. It also uses a lot of Iphone power!
A podcast from the U of Mass was scheduled for today,Dec.2 concerning mapping woodland but so far I have not been able to find it.
I have had good luck with MotionX-GPS on my iPhone. You can walk or drive your trails to create a track then export to Google Earth.
I used MotionX-GPS for a year or so, but they have discontinued support. I believe those who have already downloaded it can continue using it, but it is no longer in the app store.
As Gerry Hawkes mentioned, it was a solid app.
2+ years after your initial inquiry, but if you are still looking for a solution for using your iPhone to map trails:
Check out Gaia GPS. It will record tracks as you walk them and display them on a selection of possible maps (satellite, some topo, etc). You can also define areas (such as wetlands) and record waypoints. You can view your collected data on a webpage from a desktop computer, where you can also do some limited editing (choose colors, line weight, etc.) You can import and export the data from the app into other programs. I've ended up exporting most data to Google Earth, and viewing it on my desktop computer where I can fine-tune it to make a better-looking printable map. The free version has a limited selection of background layers (topo map or satellite view). The free version requires a cell phone signal to view the underlying background layer. Paid versions offer more map backgrounds and other features: The standard members ship adds the ability to download the background maps for use without a cell phone signal. The premium version offers more options including a map overlay showing parcel boundaries with ownership data. I use the free version, so created my own parcel boundary data (usually by creating the area in Google Earth from waypoints created at the survey pins on my property, then importing that data into Gaia GPS). I can get by just fine with the free version, though if I were operating on a lot of different properties, I'd probably go for the premium paid version for the convenience of already having property boundaries shown. Available for both iPhone and android phones, with a web interface for desktop computers. Data syncs automatically across your devices.
Sample screen shot of Gaia GPS showing my trails and wetlands:
Another good app is OnXMaps. I'm not a hunter, but I do use the OnX Hunt version. I find this much easier to use than Gaia GPS, but there is no free version (They do have a limited time free trial where you can check out most of the features.) Data syncs automatically across all of your devices. I find exporting and importing information between Google Earth and OnX much easier. The one weak area for me is that all of the user-added data is lumped into one folder. You can filter the view to just show waypoints or lines for example, but you can set up a separate folder to put all of the data on your own land, and another folder for a favorite hiking area or neighbor's land, for example. They do say they are working on adding this feature, however. Cost is about $30/year for maps of one state or $100/year for all 50 states. Mas include parcel boundaries and ownership data, which is updated (I believe once per year?) It's available for iPhone & Android phones and Garmin GPS units. A web based version can be accessed for desktops/laptops. Data syncs automatically across all devices.
I've used Gaia GPS on my android and had decent success. There is a short but real learning curve. After using it in practice once or twice and then uploading to my computer it became intuitive. I think the cost is about $40 per year, but it seems like a solid product especially for mapping trails and stand boundaries.
$40/per year is the cost for the Gaia GPS premium membership, which includes all the bells and whistles (including parcel boundary and parcel ownership information). If you don't need that, the free version will allow you to enter property boundaries yourself. (I created it from known corners of my property imported from data I already had in Google Earth - basically traced the borders from the parcel info on the town's digital tax map, but you can also do it by recording the points in Gaia GPS.) However, if you are visiting a lot of different properties, the annual premium membership is certainly worth it. Here is a link to the Gaia GPS membership levels (scroll down for a table comparing features).
There certainly is a bit of a learning curve, but if you spend a little time up front, it's not hard to get started. (It's a whole lot easier than trying to learn a full-fledged GIS program)