In Scottish island, install parking app (5)
I believe the answer is:
skype
'app' is the definition.
(Skype is an example)
'in scottish island install parking' is the wordplay.
'in scottish island' becomes 'skye' (I can't justify this - if you can you should give a lot more credence to this answer).
'install' is an insertion indicator.
'parking' becomes 'p'.
'skye' enclosing 'p' is 'SKYPE'.
(Other definitions for skype that I've seen before include "Telephone over the internet" , "Way of calling" , "Computer-based telephone software" , "Online phone service" , "Have a spoken conversation via the internet" .)