According to the latest data from comScore, Apple accounted for 24.4% of the U.S. smartphone market for the three months ending in May. RIM was once again the market leader with a 41.7% share of the market; Apple was second, followed by Microsoft with 13.2%, Google’s Android with 13%, and Palm with 4.8%. Apple’s percentage, which is based on smartphone subscribers and is taken as an average from the three month period, is down slightly…