Note that unlike some of the fee-based sync services we looked at last year, Live Sync does not keep copies of your files in the cloud: It merely serves as a conduit between PCs. Since it involves no online storage, however, it puts no limit on the amount of data you can sync. And, of course, it's free.

Live Mesh

Here's a free Microsoft service for people who do want to keep their files in the cloud. Though Live Mesh is more powerful than Windows Live Sync, it's also a bit more complicated.

Rather than synchronize files and folders from PC to PC, you create folders in Live Mesh and then have all of your PCs synchronize with those folders. With this arrangement, you can access the files and folders from any Internet-connected computer. You have an exceptional amount of control over the synchronization, too--for example, you can choose to synchronize only the files modified in the last 30 days, or those under 500MB. Live Mesh supports remote control of any PC in your mesh, as well. So far, Microsoft has announced no plans to charge for storage--or to limit the amount of data you can store.

Microsoft Office Live Workspace

Office Live Workspace will help anyone with a small business or in a workgroup who needs a simple way to collaborate on projects. With this service you can create and share documents, schedules, to-do lists, and more.

You start by creating a shared "workspace." You can choose from 11 prebuilt ones--such as a Project Workspace, a Meeting Workspace, or a Travel Workspace--or you can create your own from scratch. Each workspace has templates already created for it, including PowerPoint presentations, Excel worksheets, and Word documents. Group members can work on the documents and save them for colleagues to see and edit. To edit the Office documents, you'll need to install a free Office add-in, although anyone can view them without the add-in or Office.

Why use this rather than Google Docs or Zoho? One big, exclusive benefit is its direct integration with Microsoft Office--right within the Office suite, you can save files to your workspace, and you can use the Office programs to edit files in your workspace. On top of that, the template-driven approach to creating documents and workspaces is superior to anything you'll find in Google Docs or Zoho.

Microsoft's Virtual Earth 3D

Okay, this one isn't a Web service, strictly speaking--it's a desktop app that works with a Web service. But it's a good one: Microsoft Virtual Earth 3D.