At the fallout 3 website (www.bethsoft.com) download the geck to make mods!
Joining enables you to download bigger mods so if you like mods, Yes.
In Fallout 3, there was a site called "Fallout 3 Nexus", from what I understand it was where everyone went for mods. Similarly, one was made for New Vegas named "Fallout New Vegas Nexus". You'll be able to find all the mods you could ever hope for there (just google it). Be sure to download the Mod Manager, it makes mods easier to use.
Yes, you can install Fallout 3 PC mods from Fallout Nexus onto the PS3. For a tutorial, see: http://fallout-mods.blogspot.com/2010/11/fallout-3-mods-for-pc-on-ps3.html
there are no PC mods for Fallout 3 on PS3. Why do think they call it Personal Computer
just mods basically
If you have Xbox live. Maps on halo 3 for mods. go to bungie.net, make a profile with your gammertag and look for the mods under community. just simply type in mods under the map seciton. it will automatically download to your 360 if you click download on it. I recommend planet mod.
fallout3nexus.com
Yes.
Yes, you can mod Fallout 3 and lucky it's not to complicated. Simply download Xplorer360 or (what I recommend) Xport 360. You also need to find a Fallout 3 save editor, or the G.E.C.K. modded for use on the 360. Once you have everything you need (including some sort of transfer cable, of course) you just follow the instructions, and enjoy your mods. Also there is an EXTREMELY small chance you will get caught, because if you do it right they will never be able to detect the mods. Read for a profile tool: http://forums.techpowerup.com/showthread.php?t=77427 As for the G.E.C.K. I found a link on codejunkies.com so it will probably always be there.
Unfortunately no. The PC version is the only one that can be "modded," though you can Hex Edit the Xbox 360 version.
you cannot mod fallout 3 on xbox 360