From what I've seen on them, it looks like you could fit one on a video card without wasting a PCI slot, but it looks like a really tight fit. You can use them on the mobo chipset too, and from what I've read about active cooling on a chipset, it helps allot with stability (especially with overclocking). Abit's using active cooling on the KT7s.
As for when they come out, no idea, but I hope they come out soon 🙂.