Apple’s share of the worldwide mobile phone market (smart and not-so-smart) nearly doubled year over year in the second quarter of 2011, from 2.4% to 4.6%, according to a report issued Thursday by Gartner, Inc. That put Apple (AAPL) in fourth place among mobile phone vendors, well behind Nokia (NOK), Samsung and LG.

Apple’s share of the rapidly-expanding smartphone market grew 29% in the same period, from 14.1% to 18.2%. That put iOS (not counting iPads or iPod touches) in third place among smartphone operating systems, after Google’s (GOOG) Android (which grew 152%) and Nokia’s Symbian (which shrank 46%).

“Google and Apple are the obvious winners in the smartphone ecosystem,” declared Gartner’s press release.

“Apple continued to exceed expectations, even though the iPhone 4 will soon be replaced by a new model. Part of its growth came from the 42 new carriers and 15 new countries that it entered in the second quarter of 2011, which brought its total coverage to 100 countries. This expansion caused its inventory to grow a little by the end of the second quarter of 2011, when sales to end users stood at 19.6 million units. In mainland China, Apple is the seventh-largest mobile phone vendor and the third-largest smartphone vendor.”

Below: Gartner’s spreadsheets.