The state in which your system starts up is controlled by what's called
runlevels. There are seven, and they usually correspond to:
Code:
0 System halt
1 Single user mode
2 Local multiuser mode without remote network (e.g., NFS)
3 Full multiuser mode with network
4 Not used
5 Full multiuser mode with network and X display manager — KDM, GDM, or XDM
6 System reboot
The ones you're generally interested in are 3 (normal system boot, start in the console) and 5 (normal system boot, graphical login straight into X). To change the default runlevel, edit your /etc/inittab file and change the line that (probably) says 'id:3:initdefault:' to 'id:
5:initdefault:'
Note: I use Debian, and runlevels are a bit strange in that case - for me, installing KDM set things up correctly. However, this is how I understand most distros control booting into X, and it should work for Slack.
[Edit]Beat to the punch while reading up...