Good Syncing App

Launch terminal

Code:

man rsync

 

There are several options for you... If you really want duplicates of all your data you can use 'rsync' to keep the files between both computers there. Or you can use iTunes HomeSharing or whatever it's called to access and even copy songs between computers on your home network.

If you want over the net syncing you can try Dropbox, but you'll be limited to certain max storage without paying for more than 2GB.

Another option is to put your music files on a network shared drive on your iMac and just mount the drive on your laptop and connect to that.

My method is just using iTunes sharing. I have a lot of music on my iMac and on my Linux desktop. I can use any computer to just stream the music from the computer hosting the songs. This keeps me from wasting space storing songs more than once.

For more info on syncing check some of the other threads where I've posted where I talk about syncing documents, emails, calendars, contacts and bookmarks.
http://forums.macrumors.com/showthread.php?t=909642