I have Windows 7 as host and I am running VirtualBox with Windows 7 as guest. I have created share folder on my host but I do not know how to access it from guest. Any ideas?
Read about shared folders in VirtualBox here.
(I ran into trouble too, the other answers did not help me, but I eventually found the solution which I am sharing with you)
In a nutshell it is:
More details on Shared Folders in VirtualBox
But, if it still fails, it is probably because Guest Additions are not installed.
On Guest machine, click in the menu: Devices > Install Guest Additions...
Navigate to the virtual CD-ROM just created, and install VBoxWindowsAdditions.exe