Unfortunately I think that the FriendlyARM Mini2440 (Samsung S3C2440) is not one of the officially supported devices.
There is also another issue: The CPU supports ARMv4 instruction set so if you want slackware on it you'll haveto go back to version 13.37 or earlier because as of slackware 14 the minimum requirement is a ARMv5 instruction set capable CPU.
Note being amongst the officially supported devices means you will haveto get a working kernel for your device from somewhere else.
Once you find a suitable kernel and a way to boot it then the slackware 13.37 userland will work fine.
You might like to have a look on docs slackware for hints on how other people got slackware on non officially supported hardware:
PS: you really would be so much better off with a kirkwood based device like a sheeva plug or even a seagate dockstar