First you need to install some components:
pacman -S smbclient pacman -S gamin pacman -S smbnetfs modprobe fuse
Add the following lines to your /etc/rc.conf
MODULES=(... fuse ...) DAEMONS=(... smbnetfs ...)
And write this line inside your /etc/fstab
//servername/sharedFolder /home/user/share cifs guest,uid=1000,iocharset=utf8,codepage=unicode,unicode 0 0
guest: means there are no login credentials requierd to access this share
uid=1000: this must be your user id. With this option you get additional write access
the combination iocharset=utf8,codepage=unicode,unicode allows access to files with names in non-English languages