Research in Motion Ltd. (ticker symbol RIMM) has reported, not unexpectedly, that sales for its’ BlackBerry smartphones are slackening as competition in the smartphone marketplace continues to heat up. The warning comes just a month after the company reported earnings and gave a weak short-term outlook, providing fresh evidence that RIM is struggling to compete with Apple Inc. and other smartphone makers, especially in the U.S. market. The quarterly shortfall, RIM said, was mainly due to lower shipments of its BlackBerry phones and a greater reliance on sales of cheaper devices. The company is losing ground as new products are being delayed until later this year while RIM develops models with touchscreens and tries to shift to a new operating system. Surging sales of smartphones utilizing Google’s Android software seem to be gaining market share at least partially at the expense of the BlackBerry.

Today’s Wall Street Journal (wsj.com) reports that RIM’s PlayBook tablet computer, which has received tepid reviews, has not enjoyed a stellar debut in the marketplace. The device was placed in stores for sale earlier this month after delays in its’ introduction. The company, however, counters this claim by stating that early PlayBook sales have been in line with its own internal targets. The difficulty RIM is experiencing in gaining early traction in sales of its PlayBook tablet may be a harbinger of the headwinds other manufacturers might encounter as they release their tablet offerings to compete with the first mover advantage enjoyed by Apple’s iPad and iPad2.

“Yes this is a transition,” said co-Chief Executive Jim Balsillie in a conference call. “All things being equal, we would like this stuff to be earlier, but when you look at the performance of the Playbook….nobody doubts the absolute performance of that machine.” “And we absolutely have a whole next generation of smartphones, so strategically we feel fantastic,” he said. “Operationally, I don’t like the fact that this stuff is pushed out so you have this transition.”

For the quarter ending in May, RIM said it now expects per-share earnings of $1.30 to $1.37, down from the $1.47 to $1.55 projected last month. RIM also said it expects shipments of BlackBerry phones for the quarter to be at the lower end of the range of 13.5 million to 14.5 million it forecast in March. The company said the lower shipments and a shift to lower-priced models will result in revenue slightly below the $5.2 billion to $5.6 billion estimated forecast in late March.

No surprise the stock price, struggling to break back above its’ 200 day moving average, suffered today upon release of the announcement. Shares closed at $56.59 at the close of the regular market session, up from yesterday’s close, then fell off over 10% in after hours trading to $50.30.