Not without using mods.
Yes But You Will Probably Get Banned
there might be now because there is a new campaign on halo 3
make a folder in documents>electronic arts>sims 3>mods>packages. make a mods folder and in the mods folder make a package folder. then, go onto the website and add the mods to the packages folder! I'm warning you though, as of the newest patch, you may have difficulties with your game. I know I did and had to remove them. But, it might just be me so go ahead and try! If it dosent work, sadly, you will have to remove them.
well theres cliff mod rocket mod fishy mod night blood gultch mod jerrassic park mod sniper mod no gun mod spiner mod bumper cars elite mod pelican mod echo 116 and more i dont know because you can make your own mods
Go to www.MacGamingMods.com it will be There
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.
depends on what you're looking for. but most good mods in halo require a jtag. but a good site to look up mods is- http://www.thetechgame.com/
As of now the Halo: Reach beta is gone, your not going to be able to.
Mods.... search halo armour oblivion
You can in HALO 1 if you use mods, but it has to be on the computer.
Yes. There are a lot of mods for Halo and Halo Trail on PC.
See halomaps.org for mods like sonic for halo. It is only for Halo Custom Edition, but you can convert it to Trial or Retail with Pearl or Demo with Queene Anne's Revenge.
Yes
With lots of mods to the nerf stockade.
If there maps, go into the Halo CE files and put the map file into the file named "map" or something like that then, when you play halo it should work, but if its the menu or something you have to take out of the maps file, a file named "UI" take that out and put the one you got into it, but all the other mods are programs you just need to double click on em.
You can mod halo 2 on the computer by enabling some mods downloaded from halomaps.org, or you can make your own using those tools.