Slackins is a graphical frontend for Slackware's pkgtool suite. 
It has also some additional tools; for example, rpm2tgz, library check, 
etcetera.  You must have root privileges to start it.

It has some flaws, though. Resizing it is not that beautiful, and 
there are also some spelling issues.

Note that the slackins binary will install with root:wheel ownership
and mode 4750, meaning that it's setuid root and executable only by
root and members of the wheel group.  This should be a safe enough 
approach since this will prevent everyone else from executing it,
and even so, slackins will prompt for the root password before doing
anything.  If you don't want to install the binary suid, then run
the build script as follows:
  SETSUID=no ./slackins.SlackBuild