HRTF is exactly what's used by Dolby Headphone to generate the audio as a faux-positional source. I'm not 100% familiar with the technology behind it. The real time conversion is achieved using a finite impulse response filter (to quote dolby's site: "Dolby Headphone technology also provides all the benefits of a highly detailed finite-impulse response (FIR) filter, with virtually no latency.")
I suppose that strictly speaking HRTF is more than sound latency and volume - the way a soundwave reflects from your ear lobe, as well as the way you receive the sound changes when you move your head are things that headphones probably won't be able to simulate correctly. (interesting topic btw, I've started reading more and more about it now)
However, you can take 2 channel sounds and apply this sort of processing to it, even if it does not contain all the necessary information for full blown HRTF. It works fairly well in my opinion. When I had a chance to test this with my headphones, I had two unplugged speakers standing in front of me, and when the dolby feature was enabled, I could swear that the sound was coming from the speakers, and not from the headphones.
My main gripe is why this isn't a more commonly seen thing - I suspect that people generally aren't sure how a pseudo positional sound like that sounds when they try headphones, and are probably not willing to spend the extra buck on headphones like that.
I really want to try to find a decent pair of headphones. The ones I had before required software on your pc for the processing, and I want to see if I can find ones that work with anything!
Edit: After digging through some headphones, this is probably close to the pair, if not the exact pair, i had: http://techreport.com/review/19740/corsair-hs1-gaming-headset