Microsoft might now be wondering why they didn’t undertake a redesign of the Xbox 360 console a lot sooner. The latest data from the NPD Group shows that the June sales figures for the new Xbox 360 slim console beat everything out there, with the exception of the Nintendo DS.

For the month of June, Microsoft sold 451,700 Xbox 360 slim consoles, which beat out the Nintendo Wii at 422,500 and the Sony PlayStation 3 (which only managed sales of 304,800 units). The sales translate into a 35% jump for Microsoft when compared to the numbers in June 2009. Still, software sales remained a bit flat, which has was expected with the number of high profile titles slated for a holiday release.

As to why the Xbox 360 slim has sold so well, retail sources tell us that many Xbox 360 fans either upgraded to the new Xbox 360 slim or purchased a second console. This is actually very good news for Microsoft, as they have been struggling with hardware sales due to increased competition from Sony’s PlayStation 3.

Our retail sources expect sales of the Xbox 360 slim to continue to be strong for the next month or two, which should help better position Microsoft for the 2010 holiday season. Still, our retail sources continue to point out that while interest in the upcoming release of Kinect from Microsoft has increased, it has not yet led to additional pre-orders. Retailers that we have spoken with continue to most often cite the price as well as the lack of compelling titles as reasons they are not interested in the device.