Exactly what is oversampling?

Can anyone explain what this term actually means? I notice the new generation of inexpensive Pioneer dvd players feature 192kHz/24 bit D/A converter chips. Does this mean it's upsampling an audio signal? If so, will it perform near to, say, an Audio Aero Capital cd player which costs about $5000. Please clear this up for me.
OVER-sampling is something that nearly EVERY CD player does. Oversampling basically mulipies the frequency of the input by a number (generally something like 4x, 8x, or 32x) to match the operating frequency of the DAC. This also gets rid of some of the high frequency spuriae that some down range components (amps, preamps) may not be able to deal with.

UP-Sampling actually fundamentally changes the input itself. Instead of just merely multiplying the frequency, it actually adds bits to the input signal, well before the DAC. It helps assure that the DAC makes far fewer errors, and although it doesn't IMPROVE the signal, it helps to keep it in tact. Hope this helps. Cheers!
I forgot the second part of your question. No, just because the DAC over/upsamples, it doens't mean it's good. Or even adequate. There are SO many engineering challenges in designing quality digital equipment, and the DAC is only one small part of this equation. How well does the transport take the info off the disc? How much jitter does the clock introduce? Is the signal path clear, or cluttered? Is the DAC operating at the same exact frequency as the transport? How is the analog output stage?

There are many quality factors involved, and I would definitely go so far as to say that those Pioneer player are FAR inferior to the Audio Aero. Just my 2 cents.
Had long term play demos at last club meeting between the Aero Capital and dCS Elgar and Purcell combo. dCS was more impressive. (and more money)
I recntly changed from a Bel Canto DAC 1.1 to a Muse Model 296 and though both are true 24 bit 96 kHz upsampling DACs they by no means sound the same the Bel canto sounded very good, but the Muse is truly amazing. In addition to the imaging, detail, lack of high end hash one has is any really good DAC there is a palpability to the instruments that I have only heard elsewhere with the dCS equipment. So to anwer your question there are definately differences even when the rate of upsampling is nominally the same.
I know that a $200 Pioneer dvd player is not going to blow an Audio Aero Capital cd player out of the water. I understand that quality high tolerance parts, massive power supplies, layout architecture, and build quality have an enormous effect on sound quality. What I am asking is this: are they doing basically the same thing? If the answer is "yes" then we should expect these relatively inexpensive "mid-fi" machines to come close to state of the art, cost no object players. Furthermore, if my assumption is correct then "upsampling" should drop drastically in price very soon. Shouldn't companies like Adcom, Denon, and others be soon introducing their afforable models in the $750-$1500 range that will be high class C and B to the Audio Aero and dCS units that we now have at very deluxe prices? Comments?