Although the majority of IT experts have had a hunch for long time that the Mac adoption rate is stealing more and more potential Windows users, Needham & Co are offering now statistical data to prove this phenomenon.

According to the analysis company, more than 400,000 users chose Apple over Microsoft, and the engine that drives this trend is obviously the iPod. And now that the most well known player and the download service that accompanies it (we are talking here about iTunes) has exceeded the psychological threshold of 500 million downloads, the Mac adoption rate will increase even more.

More than that, Charles Wolf, analyst at Needham, said that Mac sales have increased 35% in the first quarter, which points out an adoption rate three times faster than the one for PCs.

And things only got better for Apple, because in the second quarter Mac sales increased 43%, a result which could have been obtained only if a significant number of Windows users had decided to switch from Windows to Apple.

Microsoft has real reasons of concern, since it will get even better for Apple. Experts estimate that by the end of the year, over 500,000 iPod users will buy a Mac system. And the changes made by the Cupertino company (switching to Intel and the launch of the Tiger OS) will only draw more and more fans.