REmote connection to Win 2003 server

Here is the situation: Have Win2003 server, STD Editon not configured with Active Directory, just plain old file sharing in workgroup mode. Four users take their laptops on the road and would like to connect to the server mapped directories to retrieve their files. What do I need to do at the server and on their laptops to achieve this? We have a SonicWall FireWall guarding the LAN, Thanks,

Jeff