two Qs

To get the armor, you need to fall through the grate thing that collapses when you walk over it and go into the sewer. The dead Brotherhood member should be right there and if he isn't then explore around down there and you'll find it.

If you mean find the disc that has Operation: Anchorage and the Pitt, then any games store should have it and if they don't then just ask if they had it in or something about getting it. All you have to do is put the disc in and it'll ask you to download an update and click yes. Then if it asks for another (which I think it will) do the same thing. Now it asks you which you would like to download and already has both selected. Just click download and it will save it onto your hard drive. If you don't have a hard drive and only have a memory card then you'll need to get a hard drive.

Hope this helps.

Once you clear the sewers of Old Olney there should be this little section where all the bodies are. Right in the middle is the Brotherhood Intitiate with the Medic Power Armor on. You can find the expansion packs for Fallout 3 on the Xbox Live Marketplace. All you do is purchase each one using 800 microsoft points(costs 10 dollars) that you buy at any game store and download. When it's done downloading you can play them. If you don't have Xbox Live you can purchase the disk DLC for the Pitt and Operation Anchorage(Broken Steel is not out yet). You buy the disk, download the update, then the content, and you're ready to go.

In the sewers the will be a body with it expanions on xbox live or buy the disc operation anch. And the pit, broken steel and piont lookout will bw out on 8/18/09 and the game of the year edition will be out 10/6/09 will the four said expansions and mothership zeta for $60

You can find it under the streets. There is a grate that you can fall through to get to it.