Yes, SAMBA is what you need. I do exactly the same on my network
There are two ways you can go about this depending on how many users you have on your windows network and what access you want them to have.
If you only have a few users, you could set up user accounts on the linux fileserver for each user giving them the same username and password as their windows accounts and each user can access the SAMBA server at their home dir. This is nice as each user can easily be restricted to their home dir if needed. Obviously this starts to get impractical if you have a large number of users.
Or if you have many users or users need to share info on the server between themselves, you can just create a shared dir and use guest priviledges to make it open to everyone on the network. You can then start restricting priviledges as required.
One thing to remember - make sure you set the same workgroup name on your SAMBA server as the windows workgroup.
Hope that helps get you started.