This script is working for me, most of this was gathered from other threads, unfortunately I have misplaced the original creators names to give credit.
Code:
tell application "Microsoft Entourage"
-- get the currently selected message or messages
set selectedMessages to current messages
-- if there are no messages selected, warn the user and then quit
if selectedMessages is {} then
display dialog "Please select one or more messages first and then run this script." with icon 1
return
end if
repeat with theMessage in selectedMessages
set theName to subject of theMessage
set theContent to content of theMessage
set theID to ID of theMessage as string
-- set the path to a temp area on your HD to temporarily store the attachment to be loaded into OF
set theFileName to "YourHDName:Users:Username:Temp:" & theID & ".eml"
save theMessage in theFileName
tell application "OmniFocus"
set theDoc to default document
set theTask to theName
set theNote to theContent
tell quick entry
set NewTask to make new inbox task with properties {name:theTask, note:theContent}
tell the note of NewTask
make new file attachment with properties {file name:theFileName, embedded:true}
end tell
activate
end tell
end tell
-- Remove the file now that it is in OF
tell application "Finder"
delete file theFileName
end tell
-- Only Uncomment if you really understand and are happy with the process and want the message to
-- be removed from Entourage after it gets sent to OF
-- delete theMessage
end repeat
end tell