Google Drive's shortcut in Windows 7/Vista shows up in your Favorites folder, while in Windows XP, it shows up in your My Documents folder. The shortcuts are easy enough to use, but if you find using a specific drive letter to be more convenient, there's an easy way to map one to your Google Drive account.
If you're comfortable using the command prompt, you can use the DOS command: subst. A better and easier way to create the drive association is using a small program called Visual Subst. It's basically a GUI front-end to the subst command.
Here's how to use Visual Subst to associate a drive letter to your Google Drive account:
Step 1: Download and install Visual Subst.
Step 2: Select the drive letter you want to associate, then type in the path of your Google Drive account, or browse to the path. In Windows 7/Vista, it should be C:\Users\Username\Google Drive, where Username is your Windows username.
Step 3: Make sure to check the box next to "Apply virtual drives on Windows startup," then hit the green plus button to add the association.
Step 4: After the association has been added, the virtual drive will appear in the Visual Subst list.
That's it. You should now see your Google Drive account as a drive letter in Windows Explorer. If you want to delete the association, just highlight it in Visual Subst and click on the red X button.