Applescript to save the foremost window in Safari as a PDF. Uses the window’s title for the file name, saves to ~/Desktop

Save Current Safari Window as PDF

Update

Uses GUI Scripting, so might not work in future versions of Mac OS X or Safari (Developed with Mac OS X 10.4.8, Safari 2.0.4 (419.3))

tell application "Safari"
    activate
    set theWindow to the first item in windows
    -- set theTitle to the title of theWindow
    set theTitle to name of theWindow
    my p(theWindow, theTitle)
end tell

on p(winObj, theTitle)
    tell application "Safari"
        if get miniaturized of winObj = true then
            set miniaturized of winObj to false
            set index of winObj to 1
        end if
        tell application "System Events"
            tell process "Safari"
                keystroke "p" using {command down}
                delay 1
                keystroke "d" using {command down}
                keystroke tab
                keystroke tab
                keystroke tab
                keystroke tab
                keystroke tab
                keystroke (ASCII character 31)
                keystroke (ASCII character 31)
                keystroke return
                keystroke theTitle
                keystroke "s" using {command down}
            end tell
        end tell
    end tell
end p