We present three projects in mobile learning. First, we polled 333 Japanese university students regarding their use of mobile devices. 100% reported owning a mobile phone. 99% send email on their mobile phones, exchanging some 200 email messages each week. 66% email peers about classes; 44% email for studying. In contrast, only 43% email on PCs, exchanging an average of only 2 messages per week. Only 20% had used a PDA. Second, we emailed 100-word English vocabulary lessons at timed intervals to the mobile phones of 44 Japanese university students, hoping to promote regular study. Compared with students urged to regularly study identical materials on paper or web, students receiving mobile email learned more (p<0.05). 71% of the subjects preferred receiving these lessons on mobile phones rather than PCs. 93% felt this a valuable teaching method. Third, we created a web site explaining English idioms. Student-produced animation shows each idiom's literal meaning; a video shows the idiomatic meaning. Textual materials include an explanation, script, and quiz. 31 college sophomores evaluated the site using video-capable mobile phones, finding few technical difficulties, and rating highly its educational effectiveness.