BlackBerry TourResearch in Motion posted first quarter results for fiscal year 2010 yesterday and, for only the second time in its history, the BlackBerry maker saw a decline in subscriber growth dropping to 3.8 million net new subscribers down from 3.9 million the previous quarter.  The rest of RIMs numbers were pretty good and the BlackBerry actually saw on overall increase in its U.S. leading market share.

“We are starting fiscal 2010 with strong financial performance and impressive market share gains, including a 55% share of the U.S. smartphone market according to IDC’s latest estimate,” said Jim Balsillie, Co-CEO at RIM. “The industry leading BlackBerry product portfolio is driving strong customer demand around the world and our penetration of new market segments continues to expand. We are particularly excited about the strength of our product portfolio for fiscal 2010 and we are looking forward to driving continued growth and profitability in our business throughout the remainder of the year.”

That may all well and good, however, the market is mostly reacting to RIM’s drop in subscriber growth and concerns that the BlackBerry is seeing increased pressure in the space from competitors such as the iPhone, Google Android devices, and the Palm Pre.  RIM’s stock price has fallen  0.67 down to $76.04 in after hours trading.

It will be really interesting to see if RIM makes a comeback this quarter while having to compete with the new iPhone 3G S, a $99 iPhone 3G, and a Palm Pre that is getting rave reviews.  RIM has released or is about to release more BlackBerry devices on more carriers at the same time than at any point in its history and I am guessing that it will be a pretty interesting summer in the smartphone market…