Mobile Phones for Learning?

​With the mobile phone now at saturation point in society how are we as educators addressing the potential these devices have for new digital learning opportunities? It is common for school authorities to place a ban of mobile phones in school and this policy is generally based on what is perceived as the potential for abuse a mobile phone can provide. There are doubtless negatives that can be associated with mobile phones but there are also many positive ways the devices can be used in learning.  Here are some links I have come across that show some of these ideas. And here is an article (PDF) from Mark Prensky (he who coined the term “digital natives”) –

Links

http://www.cellphonesinlearning.com/

http://www.getmail.com.au/wwwtools/viewpage.aspx?rid=37952

http://cellphones.org/blog/interviews/cell-phones-in-education-an-interview-with-liz-korb

http://kt.flexiblelearning.net.au/tkt2006/edition-12-editorial-2/connections-social-and-mobile-tools-for-enhancing-learning-by-leonard-low

What do you think? Can the mobile phone be used as a tool in the classroom? How can educators ensure acceptable usage practice?