For some clarity (as it's not obvious where to find the list of shares in the GUI)
As people mentioned, open a command prompt and type net share. This is probably the easiest way to see what shares are available. This will also show hidden shares (those with $ as the suffix) and where the share points to.
Here's an example:
C:\Users\tstmoss>net share
Share name Resource Remark
-------------------------------------------------------------------------------
C$ C:\ Default share
IPC$ Remote IPC
ADMIN$ C:\Windows Remote Admin
The command completed successfully.
On Windows Server 2008 either right click on Computer in the Start menu and select Manage, or launch the Server Manager (by default, the first icon next to the start menu in the task bar).
In the Server Manager, expand the Roles node, then expand the File Services node. Click on Share and Storage Management. The display will show two tabs, Shares and Volumes. The Shares tab shows you the existing shares (same as the console output above). This interface does allow you to interact with the with the share like changing properties/permissions, stopping the share, or creating new ones.
Hope that helps.