To expand on what X-Ray said...
GameStar: Will there be modding tools?
Söderlund: Well, as of now, we are not going to make any modding tools, no.
GameStar: Okay, why?
Söderlund: Because if you look at the Frostbite engine, and how complex it is, it’s going to be very difficult for people to mod the game, because of the nature of the set up of levels, of the destruction and all those things… it’s quite tricky. So we think it’s going to be too big of a challenge for people to make a mod.
http://battlefieldo.com/dice-confirms-no-mod-tools-for-bf3/
I don't see how the mod community would be able reverse engineer the game for mods/maps when you have to run the game through Origin's browser, you might be able to make them but you won't be able to load them for public play without Origin. I'm no expert on this matter and I guess there could be more to it, and I'm not being negative just realistic, so I'll have to say that I'll believe it when I see it. Hope I'm wrong though.