I don't know of any way to research who is shorting what other than SEC filings. Mutual/Hedge funds have to report this information on a quarterly basis.
The accumulation/distribution line is strongly inverse to price(It's an indicator based on buy/sell volume. Normally, an accumulation precedes price rise while a distribution is in tandem with a selloff. When shorting, the long-term trend goes the opposite way - there's more buying than selling, yet price consistently drifts down. Caveat: being based on a composite of price/volume/time, it's not totally accurate and even changes dramatically across time scales. )
Market-maker quotes on Level II behave unusually in response to buys or sells(on small, low-volume stocks in particular, MMs are sometimes colluding forces and will "paint the chart" with tiny trades that, in a fair market, would not affect quotes).
Message boards for the ticker symbol suddenly see the appearance of paid bashers who will repeat negative news multiple times a day.
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With a lot of heavily shorted stocks, the company is fundamentally weak to begin with. However, even a very solid company is vulnerable if it's starting from a low market cap. So - in general - take the appearance of a large short position as a sign to either join them or get out. To see a short squeeze the float has to be very tight, and the stock needs to be forced into a speculative frenzy with good news or just big buyers. The long-run odds always favor companies failing.
OPEN is a big-board stock with a large valuation and volume right now, so I wouldn't expect shorts to be obvious enough that you can see these indicators. As well, their dirtiest tricks are reserved for pennies. They have the lowest risk there, since market cap is so small that they can absorb most price rises.