Here's a little tidbit of information about where to find useful guidelines if you are getting into mobile services and do not know enough. MMA, the Mobile Markering Association has a number of useful guideline documents available for download as pdfs even if you are not a member of the MMA. See a select list below;
MMA Code of Conduct
http://www.mmaglobal.com/codeofconduct.pdf
MMA Consumer Best Practices Guidelines
http://www.mmaglobal.com/bestpractices.pdf
Mobile Advertising Overview
http://www.mmaglobal.com/mobileadoverview.pdf
Understanding Mobile Marketing:Technology & Reach
http://www.mmaglobal.com/MMAMobileMarketing102.pdf
Off Portal - An Introduction to the Market Opportunity
http://www.mmaglobal.com/offportal.pdf
Mobile Marketing Sweepstakes & Promotions Guide
http://www.mmaglobal.com/mobilepromotions.pdf
Mobile Search Use Cases
http://www.mmaglobal.com/mobilesearchintro.pdf
Introduction to Mobile Coupons
http://www.mmaglobal.com/mobilecoupons.pdf
Short Code Primer
http://www.mmaglobal.com/shortcodeprimer.pdf
W3C Mobile Web Best Practices
http://www.w3.org/TR/Mobile-bp/
W3C mobileOK Basic 1.0 Guidelines
http://www.w3c.org/TR/mobileOK-basic10-tests/
W3C mobileOK Checker
http://www.w3c.org/mobile
http://www.mmaglobal.com/codeofconduct.pdf
MMA Consumer Best Practices Guidelines
http://www.mmaglobal.com/bestpractices.pdf
Mobile Advertising Overview
http://www.mmaglobal.com/mobileadoverview.pdf
Understanding Mobile Marketing:Technology & Reach
http://www.mmaglobal.com/MMAMobileMarketing102.pdf
Off Portal - An Introduction to the Market Opportunity
http://www.mmaglobal.com/offportal.pdf
Mobile Marketing Sweepstakes & Promotions Guide
http://www.mmaglobal.com/mobilepromotions.pdf
Mobile Search Use Cases
http://www.mmaglobal.com/mobilesearchintro.pdf
Introduction to Mobile Coupons
http://www.mmaglobal.com/mobilecoupons.pdf
Short Code Primer
http://www.mmaglobal.com/shortcodeprimer.pdf
W3C Mobile Web Best Practices
http://www.w3.org/TR/Mobile-bp/
W3C mobileOK Basic 1.0 Guidelines
http://www.w3c.org/TR/mobileOK-basic10-tests/
W3C mobileOK Checker
http://www.w3c.org/mobile