The announcements were made at the music industry's influential five-day conference in the French town of Cannes.
Merlin said it would act as the "fifth major" in the world with a view to rectifying the "poor cousin" status of deals previously offered to independent labels.
Martin Mills, who heads the indie music organisation Beggars Group, said: "We'll be the largest major company in the world if we act together."
Indies in all the European countries as well as Australia, Brazil, Canada, Israel, Japan, New Zealand, South Africa and others have joined Merlin.
The deal with Snocap, which was founded by Napster creator Sean Fanning, is the first of its kind.
A co-founder of Myspace, Chris DeWolfe, said last year that the group hoped to be one of the biggest digital music stores available.
The hugely popular social networking website is now owned by Rupert Murdoch's News Corporation.
The major music corporations - Universal Music, Sony BMG, EMI Group and Warner Music - account for 70 per cent of world music sales.