Joystiq has posted a preview of Halo 3's upcoming Mythic map pack. They go through all 3 maps, including Sandbox, the new Forge map.

so this means the older maps will become free?

I don't know.

I'm just waiting on Halo 3 ODST. It's supposed to be less than $60 when it comes out and will include every single Halo 3 map, including these.

Not trying to be a nag, but just a reminder that Halo 3 is rated M for mature so technically this should get a restricted flag so it can be age gated. While I know it doesn't contain any mature content in this video at all, the ESRB doesn't care about the video's content so much as the game's content. You can leave it like it is, but just keep it in mind for the future. I'd like to make sure we don't get anyone in any trouble, especially ourselves.

Not that anyone would bother to sue us...

I figure if Microsoft doesn't consider the map packs to be M rated(under 18 XBL accounts can downloads them) then why should we?