Flavio21:
The simplest way to do so would take the information that comes from potentiometers (analogRead between 0 and 1023) and send it immediately by nRF24L01, right.?
Yup. Just pack it up into a payload and off you go. Each payload can go up to 32 bytes, so plenty of space for most everything you'd want to send to control a robot, I'd imagine.
Spare yourself the hassle of working out all the registers, and use a library. There is the mirf library on the playground. I also wrote my own at http://maniacbug.github.com/RF24/ . In any case, all of cpixip's advice is sound, though I wouldn't recommend sending each value separately.