UPDATE 3-Fans gather for launch of 'iPhone killer' Palm Pre

* Pre-Sprint hopes will win back market share* A small nation, New York, Chicago and San Francisco (Add a comment on the sales of phones, para 8)By Sinead Carew and Jessica WohlNew York / Chicago, June 6 (Reuters) - The small crowd gathered on Saturday at the official pre-launch, smartphone Palm Inc regarded as the best chance to claw back market share from Apple Inc in the iPhone and Research In