whatz the diff between them

how can i tell what my box is

if there is a hole in your box it is ported, if not then it is sealed

^or its just really leaky...lol

Or it had a bad termite infestation. It's been known to happen.

A ported box has one or more holes aside from the holes for the speakers. These other "holes" are called ports and they allow air to leave the box. The dimensions of the port can determine how loud your box plays at a given frequency (some can make your box play low notes louder, some can make high notes louder). Ported is generally louder because it allow the back wave of the subs to escape the box and produce sound, but sealed is harder to build and will have a flatter response.
There is also bandpass boxes where both sides of the sub (front and back) are firing into a box, but they are a little more complicated.