They provide +3.3V to the Boot pin. As easy as that. I have a cheap USB to TTL adapter that works even with windows 8, and provides +5V and +3.3V. Hooked it up to supply 3.3V to the boot pin, instead of jumpering 3.3V on the drive to boot, and voila, it is in programming mode when I attach it to pc for programming.
This is the one I use and which I see are sold with those "easy to program" goteks..