"blackberrys" or formally, "BlackBerrys"
it is a registered trademark
, so i believe that simple pluralization is acceptable, but printing an "ies" variation would constitute an infringement. although i'm no lawyer*, i would say that's probably an excusable violation. (thankfully we're not discussing the grammatically correct plurality of "NTP"
wiki has this
to say about the nicks, and within that entry you will see use of the term "BlueBerrys"
moreover, adding an 's' to the term during a search will still trap all variations, whereas 'ies' will omit many.
* and no, i didn't stay at a Holiday Inn Express last night!