If I have a save on the PS3 can I load my save from the PS3 to the PC? Can I take a save from my PS3 and download it onto my computer?

Nope.

That's a negative, Ghost Rider.

neat idea though\

Yes, neat idea, but no.

Technically you can transfer a save from the ps3 to the PC however you couldn't do anything with it they wouldn't be compatible. But if your looking to back up some save files....

No, but if you don't want to start all over you can use the console to mimic your stats, items, and completed quests

That would be cheating...
so if you don't mind being a cheater, then by all means...

I don't think it's cheating. Why you say that? If I was migrating from PS3 to PC and used the console to unlock the quests I had completed, to match my reputation points, and to get all my skills, items, and levels that I already 'earned' on the PS3 I don't see how it's cheating. You wouldn't get achievements for any of it and it's not like this is a multiplayer game where you can get 'banned'. You can do all sorts of fun stuff with the console, for instance you can summon a deathclaw in the middle of the strip or in a casino... or anywhere really.