It's available on "ABBA Gold" (video and DVD) and "ABBA - The Definitive Collection" (DVD) amongst others.
The PROMOS for 'SOS', 'Bang-A-Boomerang', 'I Do, I Do, I Do, I Do, I Do' and 'Mamma Mia' were directed by Lasse Hallström at a combined cost of less than 50,000 Swedish Kronor. These were the four songs that were felt to have the strongest hit potential from the 'ABBA' album and filmed with a view to promote it.
Thanks to Ian Cole and some info from "Bright Lights, Dark Shadows" by Carl Magnus Palm