Now you can send a birthday card to your friend’s phone right from the mobile internet. It’s only in beta testing, but the developer of BirthdayCard.mobi has an idea that’s sure to catch on. The service allows users to send an SMS birthday card to a US-based friend’s mobile number. At the moment, there are four designs with more on the way. The service is free, but recipients will be billed any mobile picture service fees from their phone carrier.