Ah. It's a line doubler. That means that all you will be doing is deinterlacing whatever signals you process through the IDC-2000; the projector's onboard scaler will still kick in to upscale/downscale whatever you feed it to the native resolution of its display panel(s).
Some will say having a line doubler is better than no line doubler at all, and if you got your IDC-2000 free or ultra cheap there's certainly no harm in trying it out. But if you actually paid money for it and can return it--and this is strictly my own personal opinion--I'd say your money would be better spent buying either a scaler or an HTPC so that you can feed your digital projector whatever native resolution that it is designed for. (And by the way, a progressive-scan DVD player will still cause your projector's scaler to kick in, so you're still at the mercy of the quality of the projector's scaling circuitry.)