ABIT uses a heavily modified Phoenix Award BIOS. The menus are basically the same as those found in other motherboards using the Phoenix Award BIOS with the exception that the overclocking menu is set up in the uGURU sub-menu. From here you can overclock the CPU, the memory and more.
The FSB can be set from 100-600MHz. Of course it's highly unlikely that a 600MHz FSB can be set on any current or future CPU, but it does give a wide range in which you can overclock. Voltage options for the CPU range from 1.4V to 1.75V in 0.025V increments. Memory voltage has a range of 1.75V to 2.3V in 0.05v increments. The last option is the PCI Express voltage control from 1.5V to 2.0V in 0.1 increments.