By the way, I found out you can't have the ODST MP disc installed and the dd copy of Halo 3 (I had to delete my ODST MP disc to download H3). Meaning if, like me, you downloaded it mostly for campaign and had all the map packs on the ODST disc, you may have to rebuy the DLC for the Halo 3 download copy.
I haven't confirmed it, but this is the way it probably works since the ODST MP disc was listed as "Halo 3"
LAME, on the offhand, the Mythic 2 map pack is on sale for $5 instead of 10 while the game is out.
YES, if you're cool with it I could put one together.