For viewing 3D on your computer, you need a monitor that supports the 3D display systems offered by companies such as NVidia. The NVidia system is called 3D Vision, and requires a monitor that supports a 120Hz vertical frequency, as it uses a pair of LCD glasses to show different images to each eye 60 times a second. Most monitors do not support this high a frequency. More details on the NVidia 3D Vision system are available here.
NVidia is also pioneering a new approach, using multiple monitors to create what it calls 3D surround video. Again, it only works with monitors that support the 120Hz vertical frequency, but the multiple monitors do offer the potential to create a more immersive effect for 3D gaming.