Fallout 3: Game of the Year Edition Tips

Haven't had a chance to try James' route, perhaps it results in better gameplay (?), but here's how I got Fallout 3 via Steam working in Crossover Games 9:

1)    Install .NET 3.0 into a brand new bottle.  You’ll find .NET 3.0 in the “Runtime Support Components” section of Crossover Games’ Install Software menu. 
2)    Install Steam into that same bottle
3)    Install Fallout 3 via Steam
4)    Copy the msasn1.dll from a legitimate, legal copy of windows that you own into the bottle’s .../drive_c/windows/system32 directory
5)    Go into Crossover’s Manage Bottles>Control Panel>winecfg>libraries menu, add “msasn1” as a new override, set it to “native, builtin”
6)    In the same menu, add “xlive” and set it to “native”
7)    Go to the winecfg>graphics tab, and set an emulated virtual desktop (to a 4:3 aspect ratio)
8)    Go to Run Command, select the Steam Bottle, type in “regedit”
9)    inside regedit, browse to HKEY_CURRENT_USER/Software/Wine/Direct3D (if you don’t have Direct3D, add it as a new key)
10)    inside Direct3D, add “useGLSL” as a new string value, and set it to “enabled”
11)    Finally, launch steam, go to launch Fallout 3.

The first time you launch Fallout 3 it will ask you to register Windows LIVE and to approve a re-install of .NET.  The .NET (re)install will take an irritatingly long time, ~20 minutes or more.  When this is done, you should be able to see and use the Fallout launch menu.

- If you go to Options, first, it will crash Fallout.  Launch Fallout, then exit, and re-launch it from the Steam Library.  Now go to options and set the screen resolution (which is 800x600 by default)

- I found that Fallout 3 has to *think* it's in fullscreen mode in order to launch, but if it's in 'true' fullscreen the mouse will continuously drop to the bottom of the screen.  For this reason an emulated virtual desktop is necessary (which is step 7, above)