That’s not just phones!  Don’t forget handhelds of all kinds.  We have to market to the little screens online now, too.  This is expanding to include wireless also, so it means laptops as well.

Email Address Cheat Sheet – What are the suffix(es) to convert a cell phone # to an e-mail address for texting?  You can link this reference-by-provider to your site for easy conversion.

eNonprofit Benchmarks

Mashable

MobileActive.org - connects people, organizations, and resources using mobile technology for social change

Mobile Giving Foundation

Mobile Marketing Association

Mobile Storm

NYCwireless
Advocates and enables the growth of free, public wireless Internet access in parks, public spaces, and affordable housing residences in New York City and surrounding areas

The Validator - Is your website mobile friendly?  Check it here.