I had been lookng for a nice easy backup solution for my University coursework which required minimal effort on my part and was cheap/free. 

I signed up to Dropbox a while ago but never really started using it properly as I had to remember to drag files over to the folder for syncing. Then I came across this great guide on how to setup Automatic Backups on your Mac with Dropbox. 

http://matthewlyle.com/mac/how-to-use-dropbox-and-automator-for-automatic-backup-of-multiple-folders/

If you're not yet signed up to Dropbox you can get an extra 250MB free with with link http://db.tt/zefDqXQ (I also get an extra 250MB so thanks in advance!)

There's a great guide on creating Custom Overlays for iOS MapKit at: http://shawnsbits.com/blog/2010/12/23/mapkit-overlays-session-1-overlay-map/ 

However it glosses over the part whereby you have to install Gdal. If your fairly new to Mac OS X and more familiar with a Windows background then you may need some extra info on how to go about it: 

Download and install the Macports.dmg from http://www.macports.org/install.php

Once installed you will need to provide yourself root privilages if you dont have so already.

• Start System Preferences and select "Accounts".
• Under the list of users press the "Login Options", and then next to that press the "Join..." button next to Network Account Server. (You will not be joining a network account server, this is just the way to get to the Directory Utility).
• Press the button to "Open Directory Utility..."
• Once you launch the Directory Utility, however you do it, then enable the root account by doing the following:
• Click on the Lock icon and give the Administrator password to authenticate.
• Pull down the "Edit" menu to "Enable Root User"
• Pull down the "Edit" menu to "Change Root Password..." and enter a good, strong password for the root user.