Yojinbo

sms-fu lets you send messages to cell phones without using a gateway.  It uses the email-to-sms features that all the US cell carriers offer for free as a convenience.

The following carriers are supported:

Alltel, Ameritech, AT&T, BellSouth Mobility, BlueSkyFrog, Boost Mobile, Cellular South, E-Plus, Fido, kajeet, Metro PCS, Powertel, PSC Wireless, Qwest, Southern Link, Sprint, Suncom, T-Mobile (US/UK/Germany), Telefonica, Virgin Mobile, Verizon Wireless, Vodafone (UK,Italy,Japan, Spain)

To add the functionality to your Rails app install the plugin from the github repository and then add the following line to your application controller:

include SMSFu

And fire off your SMS messages like this:

deliver_sms("5558675309","AT&T","your message here")