Handspring said Tuesday that it plans to start selling its VisorPhone add-on in some Asian markets later this month. Handspring said the VisorPhone will be sold in Hong Kong, Malaysia, Singapore and Taiwan through GrandTech, Handspring's Asian distributor. The add-on turns the company's handhelds into cell phones. Last month, Handspring slashed the price of VisorPhone in the United States. The device, which once cost $299, is now available in the United States for $49 with a service commitment.