If you have two Macs – for instance, a desktop and a laptop – you may often find yourself transferring files from one to the other as you prepare to head off to work or school. You may also need to send files to friends or colleagues, and in some cases file size could make this difficult. Here are some ways you can transfer files from one Mac to another.

Try email

The first, and easiest, way to send files is to email them. This will probably work for the majority of files you need to send to others, and can even work for transferring files to another Mac you own. Just add attachments to email messages and send them. If you have an IMAP account, send a file to yourself, and it’ll show up in your inbox on both of your Macs. (Not sure what IMAP is? See Four Reasons to Switch to IMAP at www.macworld.com/7058). Watch out though, email attachment sizes are usually limited. Many internet service providers limit them to 10MB, though Apple’s MobileMe will accept up to 20MB.

Use file sharing

If both Macs are on the same network, open System Preferences, click Sharing, and select File Sharing in the left pane. Open a Finder window on one Mac, and the other Mac should now appear in the Shared section of the Finder sidebar. Click on the computer’s name and enter a username and password, or connect as a guest. Now you can put files in the Drop Box folder inside the Public folder.

Another option is AirDrop, the new file-sharing feature coming in Mac OS X Lion. This allows users within a 9-metre radius to transfer files wirelessly.

AirDrop finds other users in your vicinity – even if there’s no WiFi network – and allows you to exchange files with them. Select the AirDrop item in the Finder’s Sources sidebar to see the icons of other AirDrop users on your local network. To share a file, drop it onto the icon of the person you wish to send the file to. The receiving party will see a notification asking them if they’d like to accept or decline the transfer. 

Use a shared disk

If you have an AirPort Extreme Base Station or Apple’s Time Capsule, you can connect a hard disk to those devices’ USB ports. Set up your Extreme or Time Capsule as a shared disk in AirPort Utility (in your /Applications/Utilities folder), and you’ll be able to see it in the Shared section of the Finder sidebar. Copy any files you want to that disk – you may want to make folders for different users, if you have several – and others can get the files whenever they want; their computers don’t have to be on at the same time, as they do with file sharing.

Sync with Dropbox

If you often work on two Macs, get a free Dropbox account (www.dropbox.com) and sync your Dropbox between those two computers. Put the files you’ll need on the road in your Dropbox folder on your desktop Mac, and you’ll find them in the Dropbox folder on your laptop. In addition, you can access the same files from the Dropbox website if you need to.

Send files to others via Dropbox

Dropbox makes easy work of syncing files across your own Macs, but using the service to transfer a file to a friend or colleague is just as easy. Look inside your Dropbox folder and find the Public folder. Put a file in that folder, and then Control-click (or right-click) on it and choose Dropbox > Copy Public Link. Once the file has synced to the Dropbox server, you can send the link you copied to anyone to let them download a copy of the file.

Use Apple’s iCloud

Soon there will be a new option for syncing and sharing documents. Apple’s iCloud is Apple’s internet-based service for syncing files and data across iOS devices, Macs, and PCs. You get 5GB space for free (and Apple will probably let you buy more). iCloud can sync your contacts, calendars, email, and Safari bookmarks between iOS devices and computers. It will also offer document storage, photo storage, and music-syncing features, along with backup features for iOS devices.

However, unlike Dropbox, which is designed to let you sync any file or folder on your computer, iCloud is focused on integration with apps. This means you won’t be able to use iCloud to sync a document created in a program that lacks iCloud support. 

Presumably, most iOS and Mac developers will get on the iCloud bandwagon, but there will be a period where some apps will sync with iCloud and others won’t. That means users will need to be careful not to assume that all their files are automatically saved to iCloud, because only some apps will be able to do the job. Apple hasn’t confirmed this yet, but we think it’s only a matter of time before you’ll be able to sync your application and system settings, and perhaps even your login sessions, between your Macs.

Use iChat file transfer

If both Macs have iChat configured, find the name of the person in your iChat Buddy List, and drag the file or folder onto the name. If that person accepts the transfer, the files will go right to the other Mac in a jiffy. If you want to send a file to someone on your network who doesn’t have an iChat account, enable Bonjour in both Macs’ Accounts preferences in iChat. (Apple’s Bonjour system detects users on a local network.) Once it’s enabled, display a list of available users by choosing Window > Bonjour List, and drag a file onto a user’s name.

Burn CDs or DVDs

Do you have a lot of files? Sending them the old-fashioned way might be best. Burn a CD or DVD with the files and mail them or hand them to the people who need them. In the Finder, choose File > New Burn Folder. Drag your files into the folder and then click Burn. This way isn’t useful for copying files to another Mac you own, but it can be a good way to give a number of people the same files; just burn several copies of the disc.

Pull your thumb out

When all else fails, or when you have a huge amount of files to transfer, just using an external hard disk, or a USB thumb drive may be the best solution. Connect the disk to one Mac, copy the files over to it, and then unmount it and connect it to the other Mac. If you’re copying, say, tens of gigabytes of music or video files from one Mac to another, this is probably fastest.