Run the following:

sudo apt-get install samba samba-common-bin

Set a Samba password for a user with this command:

sudo smbpasswd -a USERNAME

Add the following to the end of /etc/samba/smb.conf

[SHARENAME]
path = /home/path/to/folder
available = yes
valid users = USERNAME
read only = no
browsable = yes
public = yes
writable = yes

Then run:

smbd restart

See this post for information on accessing shares from other Linux machines.