This Xcode User Script will open the current Xcode document in TextMate. Below are the Xcode settings.
#!/bin/sh
editWithTextmate=`/usr/bin/osascript <<EOT
tell application "Xcode"
tell active project document
tell window 1
set docPath to associated file name
end tell
end tell
end tell
do shell script "mate " & quoted form of docPath`
echo editWithTextmate
