User space application for CIFS

There used to be smbmount and smbfs, but both seem to be more shipped with recent Linux distributions. They may still be available on older distributions. There are also smbnetfuse and fusesmb which both seem to offer a whole network of SMB servers on a single mountpoint. (I've tried fusesmb once but didn't get it to work.)

Besides the already mentioned GVFS, KIO and smbclient, there are also two more "browser" like tools for browsing SMB shares: smb4k (advanced share browser for KDE) and smbc (curses based SMB network browser).

If you need it to be accessible as a regular filesystem, then it must be mounted – whether via cifs.ko or via FUSE – there's no good way around that.

Though, GNOME, Xfce or KDE programs have their own virtual filesystem layers, called Gvfs and KIO respectively. Both allow you to access smb://server/share/... within the program, as long as the needed clients (gvfs-smb) are installed.

(In theory, it would be possible to craft something similar which could be loaded into any program. But I haven't seen any attempts to do so; I guess it's sort of a waste of time given the existence of FUSE.)

Finally, if you only need to transfer a few files, you could use the ftp-like smbclient tool.