Android engineering director Dave Burke in a chat today confirmed that the version of Android for phones beyond 2.4, Ice Cream, will bring many Android 3.0 elements to phones. The OS should carry over the holographic look as well as the top action bar, which brings context-specific actions and will replace many of the press-and-hold commands. Burke told Phone Scoop that the bottom bar likely wouldn't carry over; no reason was given, but space constraints could be a factor.
Multitasking should also have the visual, thumbnail-guided interface.
Ice Cream wasn't given an official timeline, but it may show at Google I/O, now locked in for May 10. Android 2.4 will only just be shipping at that stage and could lead to Ice Cream not arriving until sometime afterwards. Early plans for Ice Cream phones may have already been tipped off with a buttonless HTC phone spotted in Verizon garb.