Yes, you need Samba, which I have not found for the maemo OS yet.

What I do instead is have the open-ssh package installed on the NIT. Then I use Winscp (a freeware program) or cuteftp on Windows to access the NIT and do the kind of drag-n-drop file transfers you are looking for. A couple of added benfits of the ssh protocol is that it is secure, and it works across the internet. I also find it generally find it troubesome than that Window file sharing mess.