If you have an Apple Mobile Device (iPhone, iPad, or iPod touch) it's actually possible to sync it with multiple computers. You just have to understand the rules. Apple groups things into four categories:
Data – the data or info category consists primarily of things like your contacts, calendar, bookmarks, notes, email accounts, etc. This information can either be sync'd via iTunes or wirelessly via MobileMe or Microsoft Exchange (although Notes currently can only be sync'd via iTunes).
Media – the media category consists of your music, movies, music videos, TV shows, podcasts, audiobooks, ringtones, iTunesU and now iBooks. This content can either be sync'd or managed manually.
Photos – well this category is pretty self explanatory. It's your photo library and all of your photo albums. Your photos can either be in iPhoto or simply in a folders and subfolders.
Apps – last but certainly not least is your Apps that you've downloaded from the App Store.
Now that you know what the four categories are the content from these four categories can live on one, two, three or four different computers.
read the full details at macgroup.org