There are lots of different versions of Linux and it is fun to try them. However, you can't always install them on a real PC and it is better to try them out in VirtualBox. Here is a common scenario: You run Linux in VirtualBox in Windows. You want to access files on the Windows disk from Linux in VirtualBox or save files in Linux and access them in Windows.
One way to do this is to set up a shared folder in VirtualBox settings and then mount it with a terminal command in Linux. This is often possible, but it isn't always straightforward because you have to install the Linux guest additions and with some distros it's hard to get them working. There is a simpler way of connecting to a Windows PC's shared folders.
In Linux Mint 12 for example, open your home folder and the Nautilus file manager window is displayed. In Ubuntu just go to the menu bar at the top of the screen. Select File, Connect to server. Set the type to Windows Share and in the server box enter smb://192.168.1.64 - replacing the IP address with the one the Windows PC is using.
Finding out a Windows PC's IP address is straightforward. In Windows Vista and 7 right click the network icon at the right side of the taskbar and select Open Network and Sharing Center. In the active networks list is the network you are currently connected to, such as Home Network. On the right is the connection - Local Area Connection it says on mine. Click it, click Details and in the window that is displayed the IPv4 address is 192.168.1.64 or something similar. Your PC could use different numbers. Just make a note and enter them into the connect to server box in Linux.
Back in Linux, click Connect and you are asked to enter your username and password. These are the ones you use to log on to Windows. That's it. You should see the folders on the Windows PC. Connecting to a Windows 7 PC, you can see the Users folder and opening this gives you access to your private folder, the shared Public folder and so on.
If the IP address of the Windows PC is unlikely to change, you could bookmark the folder and save typing in that smb command each time. This is a lot easer than messing around with complex terminal commands to mount a shared folder. It works if you want to access a Windows PC elsewhere on the network from a Linux PC too. In fact, that is what it is designed for. I just use it to transfer files in and out of Linux in a VirtualBox.