The icons on the upcoming BlackBerry 10 devices have been the topic of much debate, with most people agreeing that the current ones do not look good and preferred the original look when the OS was first introduced. RIM also seemed to be listening. Soon after this, the design specifications guideline for developers was changed to suggest they should make their icons 114 x 114, smaller than the current 150 x 150 size. Today this has been confirmed via the BlackBerry Developer Blog along with an example of what the new icons will look like.
While your current 150 x 150 icons will be scaled down to 114 x 114, it is probably best to adjust the size yourself. This would be also be the best advice for those porting their BlackBerry PlayBook app to BlackBerry 10 devices. PlayBook icons are currently 86 x 86 and scaling these up would like much worse than scaling down.
A BlackBerry 10 Dev Alpha OS update will be dropping later this month to allow this change to take effect, giving you a chance to make sure you icon stands out and look great.
Source: BlackBerry Dev Blog