OS X Server absolutely will, using Windows Services (which is basically just a pretty frontend to Samba.) If you'd rather not spend the money on buying Server (you don't need all the extra stuff OS X Server brings with it, you just need a fileserver), I'd reccomend setting up a normal box (preferably a G4) with OS X Client on it, and download and set up Samba. That'll let you share files with your Windows clients on your network, and Mac clients could still transfer files by the normal means (Appletalk, AFP over IP, etc.)
Oh, and don't forget that you can set up FTP access to allow your windows clients to access your files, too.
HTH