Ah, to be young and wireless: passing digital notes in class, cheating on tests with a keystroke, challenging a pal to virtual checkers… It’s all possible with Cybiko, a translucent, Palm-style computer for teens that makes the Game Boy look like kid stuff. The handheld device, launched in New York City in April by Cybiko, Inc. (www.cybiko.com), includes a small keyboard, rechargeable batteries, and date and phone books; it can download applications and games from the Web and help you find and chat with anyone within walkie-talkie range. At New York City’s LaGuardia High School of Music and Art (otherwise known as the Fame school), Cybiko is already a must-have toy. Raphael Schklowsky, a senior who starred in the Spring Drama Festival production of Stage Door, knows at least 30 kids who own one and says that a dozen classmates appear on the on-screen people finder whenever he scans the lunchroom. He won his Cybiko outside a Sony megaplex in Manhattan, where ”street team” contests attracted such mobs that they had to be temporarily halted when 650 teenagers showed up. Sales have been brisk enough that retailers have pushed for a nationwide rollout of the $129 gadgets at the end of May. Since it already lets you send photos, and has an expansion slot that will soon support an MP3 player, Cybiko seems destined to become the recess-entertainment device du jour — at least until schools ban it.