CitiGroup analyst Tony Wible recently recommended in a note to clients, the purchase of Sirius XM Radio Inc stock. He wrote of a new streaming application from Sirius that will allow customers to listen to satellite radio on their iPhones. Tony Wible mentions that this app will help Sirius XM by eliminating their costs of buying physical radios and by making it easier for Sirius subscribers to buy tracks from Apple’s iTunes store. Sirius and XM have both been experiencing slow subscriber growth and the iPhone app may change this. However the blog Silicon Alley Insider notes that the iPhone is rather unsuitable for the purpose of listening to radio in a car where Sirius satellite radio does best. They also pointed out various factors such as lack of unique content other than the Howard Stern show that might hinder Sirius XM in this venture.