http://mostlyexchange.blogspot.com/2009/09/sending-e-mail-as-sms-or-text-message.html
Really useful answer by Michael W. on the Microsoft TechNet forums. If you want to send a text message from an e-mail client, most carriers allow you to do this. You send an e-mail message to number@emaildomain. For example, if you want to send a message to a T-Mobile user whose phone number is (808) 555-1234, then you would address the message to 8085551234@tmomail.net Keep in mind that the recipient may have to pay a "per text message" charge. Below are the US carriers. For more, see this link.
UNITED STATESn@teleflip.com Teleflip
n@message.alltel.com Alltel
n@paging.acswireless.com Ameritech
n@txt.att.net ATT Wireless
n@bellsouth.cl Bellsouth
n@myboostmobile.com Boost
n@mobile.celloneusa.com CellularOne
n@mms.uscc.net CellularOne MMS
1n@mobile.mycingular.com Cingular
n@sms.edgewireless.com Edge Wireless
n@messaging.sprintpcs.com Sprint PCS
n@tmomail.net T-Mobile
n@mymetropcs.com Metro PCS
n@messaging.nextel.com Nextel
n@mobile.celloneusa.com O2 / Orange
n@qwestmp.com Qwest
n@pcs.rogers.com Rogers Wireless
n@msg.telus.com Telus Mobility
n@email.uscc.net US Cellular
n@vtext.com Verizon
n@vmobl.com Virgin Mobile
