config.txt for (Raspberry PI) + (HDMI to VGA Video + Audio Adapter)

Here's our known-good /boot/config.txt which will set the resolution to 800x600 and enable the audio out of the adapter. we have a couple other resolution options documented as well!:

# uncomment if you get no picture on HDMI for a default "safe" mode
#hdmi_safe=1

# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan
#disable_overscan=1

# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
#overscan_left=16
#overscan_right=16
#overscan_top=16
#overscan_bottom=16

# uncomment to force a console size. By default it will be display's size minus
# overscan.
#framebuffer_width=1280
#framebuffer_height=720

# uncomment if hdmi display is not detected and composite is being output
#hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)
hdmi_group=2
hdmi_mode=87
# Put your VGA monitor resolution below
# hdmi_cvt =       
# width        width in pixels
# height       height in pixels
# framerate    framerate in Hz
# aspect       aspect ratio 1=4:3, 2=14:9, 3=16:9, 4=5:4, 5=16:10, 6=15:9
# margins      0=margins disabled, 1=margins enabled
# interlace    0=progressive, 1=interlaced
# rb           0=normal, 1=reduced blanking

# For example, 800x600 @ 60 Hz
hdmi_cvt=800 600 60 1 0 0 1
# or maybe 800x480 @ 60 Hz
#hdmi_cvt=800 480 60 6 0 0 1
# or, 1024 x 768 @ 50 Hz
#hdmi_cvt=1024 768 60 1 0 0 1
# or if you're not sure, nothing beats 640x480
#hdmi_cvt=640 460 60 1 0 0 1

# see http://www.raspberrypi.org/forum/viewtopic.php?f=29&t=24679

# uncomment to force a HDMI mode rather than DVI. This can make audio work in
# DMT (computer monitor) modes
###############################################################
### THIS LINE IS WHAT ENABLES THE AUDIO OUT OF THE ADAPTER! ###
hdmi_drive=2
###############################################################

# uncomment to increase signal to HDMI, if you have interference, blanking, or
# no display
#config_hdmi_boost=4

# uncomment for composite PAL
#sdtv_mode=2

#uncomment to overclock the arm. 700 MHz is the default.
#arm_freq=800

# for more options see http://elinux.org/RPi_config.txt

[Taken from http://www.adafruit.com/products/1151#Technical_Details]