I only know of SMB clients, not servers yet. There might be one out there though.
A temporary solution is to use SwiFTP. It will initialize a FTP server on your phone and then you can manage your files through any FTP client. If all you need it for is uploading/downloading files between your phone and PC, it might do the trick.
Did a little more Googling, and this may do the trick.
I found an app called "Samba Filesharing". Its a root app, but it should work.