You're at home and want to edit a file that's on your work computer. You're on the family PC and want to see a photo you saved on your laptop. Most of us use several different computers on a day-to-day basis, but our files aren't always where we are. Three products make sharing and syncing information across all the computers you use each day easy and free.
Google Docs is an online office suite--kind of like having Microsoft Office in your Web browser. You can create word processor documents, spreadsheets,and PowerPoint-like presentations in Docs just by logging in with your Google account from whatever computer you're on. You can also export those documents to files you can work on in your regular office software, or email them as an attachment. Google Docs also lets you upload any kind of file you want--like photos, MP3s, or video files--up to 250MB per file, and up to 1GB of those files for free. So instead of carrying around a 1GB thumb drive, you can store files at Google Docs and get to them wherever you need them.
Google Docs is great for creating new documents, but if you've already got a bunch of files you want to sync between computers, check out Dropbox. You download Dropbox for free for your Mac or PC and create an account, and it creates a special folder called a dropbox on your computer. When you save files to that folder, they automatically get synced to all your other computers that also have Dropbox installed. Your Dropbox files are also available on the dropbox web site, and there's a Dropbox app for the iPhone, too.
Finally, if you're the type of person who wants to easily capture ideas and things you see while you're online or out and about and access them from any computer, check out Evernote. Evernote's different from Google Docs or Dropbox in that it's a note-taking application, but everything you capture in Evernote you can access from anywhere, including files. So, here's how Evernote works: You install it on your computer or on your smartphone, and then as you work, you can save anything you want to Evernote, like Web pages, files,even photos you take with your phone. Evernote does some smart stuff, too: If you're walking down the street and you see a flyer for a garage sale on Saturday, you can snap a picture of the flyer with your cameraphone, save that image to Evernote, and Evernote recognizes the text on the document. Back at your computer, if you search for the words "garage sale" Evernote will show you that flyer. You can snap photos of whiteboards or business cards and search for the text that appears on them in Evernote, and you can leave yourself voice memos, too.
So, depending on the kinds of information you want to sync or capture and access between computers, check out Google Docs, Dropbox, or Evernote.