Bansky explained everything right: OpenGL is just another API (Application Programming Interface, i.e., a convention for software or software/hardware interaction). OpenGL was first implemented on Unix platforms and then ported to PC. Every video card/video chip manufacturer supplies libraries, which enable OpenGL support by this particular hardware.

The problem with your setup will be that Intel "Extreme Graphics" is extremelly slow comparing to a "real" graphics card. After you get the sim running and after you get disappointed by its frame rate (i.e., non-smooth picture movement), do yourself a favor: buy a video card.

If your system has an AGP slot (many systems with integrated video don't have one), you can still buy a PCI card. AGP is better, though. From the current crop of budget video cards, GeForce cards are arguably the best (at least, driver-wise), just try to buy not an MX version (though MX aren't bad too).

Hope this helps,
Boris