Creates a new slideshow in iPhoto with a chosen name. Replace NameGoesHere with your choice. (Requires UI scripting enabled.)
--Create New iPhoto Slideshow
tell application "iPhoto"
activate
end tell
tell application "System Events"
tell process "iPhoto"
tell menu bar 1
tell menu bar item "File"
tell menu 1
click menu item "New Slideshow"
keystroke "NameGoesHere"
keystroke return
end tell
end tell
end tell
end tell
end tell