Update: There is now a much easier way to auto-start XBMC on Apple TV boot.
See details here.
I’ll leave the below post here for posterity…

Here’s how to have XBMC auto-start when your Apple TV boots.

Create a text file with the following content:

`

<?xml version=”1.0” encoding=”UTF-8”?>
<!DOCTYPE plist PUBLIC “-//Apple Computer//DTD PLIST 1.0//EN” “http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version=”1.0”>
<dict>
<key>Label</key>
<string>com.teamxbmc.xbmc</string>
<key>OnDemand</key>
<false/>
<key>ProgramArguments</key>
<array>
<string>/Applications/XBMC.app/Contents/MacOS/XBMC</string>
<string>-fs</string>
</array>
</dict>
</plist>

`

Save it on your Desktop, as com.teamxbmc.xbmc.plist

Create another text file with the following content:

`

<?xml version=”1.0” encoding=”UTF-8”?>
<!DOCTYPE plist PUBLIC “-//Apple Computer//DTD PLIST 1.0//EN” “http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version=”1.0”>
<dict>
<key>Label</key>
<string>com.teamxbmc.xbmchelper</string>
<key>OnDemand</key>
<false/>
<key>ProgramArguments</key>
<array>
<string>/Applications/MultiFinder.app/Contents/Resources/xbmchelper</string>
<string>-v</string>
<string>-u</string>
</array>
</dict>
</plist>

`

Save it on your Desktop, as com.teamxbmc.xbmchelper.plist

Install both files to your AppleTV using Terminal.app:

`

scp ~/Desktop/com.teamxbmc.xbmc.plist frontrow@your_appletv_ip_address:.
ssh frontrow@your_appletv_ip_address
sudo mv com.teamxbmc.xbmc
.plist /Library/LaunchAgents/
sudo chown root:wheel /Library/LaunchAgents/com.teamxbmc.xbmc.plist
sudo chmod 644 /Library/LaunchAgents/com.teamxbmc.xbmc
.plist
launchctl load /Library/LaunchAgents/com.teamxbmc.xbmc.plist
launchctl load /Library/LaunchAgents/com.teamxbmc.xbmchelper.plist

`
That’s it. You can then delete the two files left on your Desktop.