Google Voice, email to SMS gateways, and several websites allow users to send free SMS from computers to mobile phones. To use Google Voice, navigate to Google.com/Voice, sign up for a number if necessary, and click Text in the top left. To use an email to SMS gateway, open an email application, enter the recipient's phone number and carrier gateway, and compose a message. To use an SMS website, navigate to TextEm.net, TXT2Day.com or SendSMSNow.com, and fill out the form.
Google Voice is free for all Google users and allows users to make free calls or send text messages to most phones in the United States and Canada. International text messaging and calling is also available at relatively low rates.
Most major mobile phone carriers provide email-to-SMS gateways. They allow emails to be sent as SMS messages. For example, to send a text message to an AT&T mobile phone with the number (123) 456-7890, write an email to email@example.com. The major drawback of this technique is that it requires the sender to know the recipient's mobile carrier.
The free SMS websites, TextEm.net, TXT2Day.com and SendSMSNow.com, are easy to use and feature simple forms for the recipient's phone number and the message. On TextEm.net and TXT2Day.com, the sender must know the recipient's mobile carrier. SendSMSNow.com does not have this restriction.