There are several ways to do that:
1. The typical usage of the IBIS file is to set up a simulation on an IBIS compatible simulator and have the IO output IBIS model drive a PCB trace with a receiver input attached at the end of the PCB trace, then view the waveforms.
2. User can use an IBIS model viewer such as the Hyperlinx Visual IBIS Editor to view the IBIS models for a specific load condition.
3. User can simulate the IBIS model with HSPICE / Hyperlinx.