Whats needed :
Sata HDD ( example : Seagate Barracuda 750GB, SATA II NCQ )
Sata Male>Female extension ( See here - Get here )
1) Open bay cover
2) Connect male end of extension cable to your ps3 internally.
3) Connect female end of extension cable to your hard drive
4) Boot ps3 and format drive from xmb.
There you go, 750gb of hard drive space on your ps3 just like mine :)