It appears as though Google is still setting up accounts too, so if you log in to the Drive site, You may see a message near the top-right that says “Your Google Drive is not Ready Yet”. More details to emerge as the service comes online. You should expect to see synchronization utilities for Windows and OS X to beginning with.

Update 1: And the details are rolling in, you can find out more from Google’s official blog (read it here).

Update 2: After using Google Drive for a couple days, here are some things I’ve learned:

1. Don’t use a “.” to begin collections/folders – if you use OS X, these leading periods will make the folders in question hidden on the Mac and you may think the files aren’t actually there. Google Drive will let you create them, but avoid it.

2. Google Drive doesn’t handle folder name changes so well – Be careful when changing folder names while Drive is syncing.  I’ve seen in one case where the folder change causes Google Drive to display an error for the files and data loss is possible (!).