In Windows 7 the concept of HomeGroups was introduced.
HomeGroups simplify file and printer sharing between computers running Windows 7 on the same home network.
Two or more Windows 7 computers can share documents and media, including stream the media between computers; and also connect printers.
In Windows 8, you can get to this from the Charms > Settings > More PC Settings > HomeGroup
There are several different options here.
You can join a Homegroup by typing in the password.
Below that, you can decide to share certain types of files on your computer: