You can open Looking4Cache Pro from other apps. For this there are some urls you can open form all other apps or websites in iOS.
l4cpro://opencache?cache=GC1234 opens the geocache detail view.
l4cpro://opencache?cache=GC1234&view=createlog opens the log editor for this geocache.
Possible values for the view parameter:
l4cpro://addwaypoint?cache=GC1234&name=WaypointName&lat=49.123&lon=9.123