Now that spring is in full bloom, the smartphone kingpins of the world are getting ready for another summer showdown. Last year's scuffle ended up a three-way contest among Apple (NASDAQ: AAPL), Research In Motion (NASDAQ: RIMM) and Palm (NASDAQ: PALM): The iPhone 3GS, the BlackBerry Tour and the Pre were all released amid hype and hoopla during the June timeframe. This year there are numerous smartphones on the horizon, including a new iPhone, the HTC Evo 4G and others. How are the market's handset vendors positioning themselves for the summer smartphone skirmish? Slideshow