Intel AMT is part of the vPro Platform. Recent intel-chipset based business machines should have it. My fairly new Intel SDV machine has it too.
Most useful to get started: "Intel AMT Deployment and Reference Guide"
You must do that from a remote host as the NIC intercepts network packets for AMT, thus it doesn't work from the local machine as the packets never pass the NIC then. If everything is fine you'll see a greeting page with a button for login.
You can login now, using "admin" as username and the password configured during setup. You'll see some pages with informations about the machine. You can also change AMT settings here.
If you have activated AMT and SOL the linux kernel should see an additional serial port, like this on my machine:
[root@xeni ~]# dmesg | grep ttyS2 0000:00:03.3: ttyS2 at I/O 0xe000 (irq = 169) is a 16550A
Edit initab, add a line like this:
S2:2345:respawn:/sbin/agetty ttyS2 115200 vt100-nav
You should add the serial port to /etc/securetty too so you are able to login as root. Reload inittab ("init q"). Use amtterm to connect. Tap enter. You should see a login prompt now and be able to login.
You can also use that device as console for the linux kernel, using the usual "console=ttyS2,115200" kernel command line argument, so you see the boot messages (and kernel Oopses, if any).
You can tell grub to use that serial device, so you can pick a working kernel for the next boot. Usual commands from the grub manual, except that you need "--port=0xe000" instead of "--unit=0" due to the non-standard I/O port for the serial line (my machine, yours might use another port, check linux kernel boot messages).
The magic command for the Xen kernel is "com1=115200,8n1,0xe000,0" (again, you might have to replace the I/O port). The final '0' disables the IRQ, otherwise the Xen kernel hangs at boot after enabling interrupts.
It is probably a good idea to assign a separate static IP address to AMT then. I didn't manage to switch my machine from DHCP to static IP yet though, the BIOS refuses to accept the settings. The error message doesn't indicate why.