Palm Inc. (NASDAQ: PALM) is just under a week into the launch of its groundbreaking Pre smartphone, and so far the wireless handset is a great seller for exclusive partner Sprint Nextel Corp. (NYSE: S). Former Apple Inc. (NASDAQ: AAPL) executive Jon Rubinstein, who was brought in to reinvigorate Palm and who is largely credited with the Pre, will now take over the Palm CEO spot from longtime CEO Ed Colligan.

When three top execs leave a company in the space of only three months, many start questioning what's happening and how the changes will impact the company's prospects. When I started digging into the recent Apple departures this morning, I found that it certainly appears that most of the changes were planned far in advance and the reins were passed on before the changes took place. Still, I think Apple could have done a much better job of communicating the change to its investors and avoided stirring up any fears about its future

Yesterday, I wrote about Nancy Heinen's departure, the third top Apple executive to leave the company in 2006. Jon Rubinstein and Avie Tevanian left in March. I quickly checked Apple's press releases and saw no formal announcements of any of these departures. Many companies announce far in advance when key personnel decide to leave and tout their replacements, to avoid any unnecessary questions. Apple likes to keep such things secret and this sometimes hurts more than it helps.

All three execs joined Apple in 1997 when Apple bought NeXT and Steve Jobs took back the reins at Apple. All were hired by Jobs at NeXT and worked with him for about 20 years. I can't say I'm surprised to hear they are ready to move on.

So why all the changes and what will happen to Apple now?