I have - it's super easy depending on which version you have. And it works GREAT... i have a couple 2TB hard drives with over a hundred PS3 games you can take a copy of if you end up modding yours.
It was a few years ago that I did it, but I followed this guy's video... again, couldn't have been easier and I did it for 3 PS3s without issue:
Should check to see if he has a newer video to follow... the modding tutorials change quite frequently and there is likely a newer one avail to follow these days.
And I have also played retro games on it (nes, snes, genesis, turbo grafx, etc), works super slick!