Syncing between Mac and iOS
This page is a work in progress about syncing (synchronizing) files, apps and other content between Mac computers and iOS devices (iPhone, iPad, iPod touch).
Single files
It is easy to sync files between Mac and iOS devices via iTunes. Say you want to transfer a Keynote file in order to make a presentation from your iPad (see our page "Making the most of Keynote"). Go to the device shown in the iTunes pane, click Apps at the top, scroll down to the list of apps that can sync files via iTunes, select Keynote (also works for Pages/Numbers), click the "Add to" button, search the Mac for the desired files, select, click "open" and voila! the file is synced to the device. No need to go through the whole syncing process.
Explore your iOS device
iExplorer is a very useful free program to move files on/off your iOS device from a Mac or Windows computer.
Syncing from iOS to a new computer
Apple's syncing process normally works by syncing an iOS device with a particular computer. If you need to backup to a different computer, take care, because it will expect you to erase the iOS device and sync from the computer.
But it can be done. This page at HowToGeek.com gives a guide for doing it free. At the end of that page it suggests a couple of paid utilities that can do some of the work for you.
Credits
Compiled in December 2012 by Neville Reid. The page at HowToGeek.com was recommended by Hank Lee.