iPhone 3G 'siphons' sales from other smartphones

Sales of the Apple iPhone 3G "siphoned off sales from other smartphone vendors" in July, according to Morgan Keegan analyst Tavis McCourt.  The iPhone 3G is the top-selling smartphone at AT&T stores, followed by the Blackberry Curve, Samsung Blackjack 2, Palm Centro and Blackberry Pearl.  At Verizon and Sprint stores, the top three selling smartphones are the Blackberry Curve, Palm Centro and Blackberry Pearl.