prepreg is exactly that, carbon fibre cloth pre impregnated with resin (its slightly sticky to touch), much higher quality and strength (same as F1 etc etc)
prepreg cloth must be refrigerated because the resin inside the colth is heat senstive. To harden the cloth - the mould with the layed up carbon is wrapped in a breather material then vaccum bagged and put into an autoclave for anywhere from 4 hours upto 24hours, not only is the mould under vaccum, but the pressure inside the autoclave is ramped up (300psi + in some cases) and the temp is ramped up to over 200degC. the heat and pressure forces the resin out of the cloth and into every part of the mould so in theory you get the same thickness throughout the part (depends on how well "layed up" it was)
with all these "cool" bits for your cars they are wet lay carbon, this is 100% dry cloth, no resin (same process as laying up fibre glass, whack the cloth into the mould and pour on the resin) nothing overly special about it, looks pretty, thats it
there are bucket loads of other resin infusion processes etc, any questions just ask (yes i know about composites, i was taught by the ex prodrive composite bod)