Can you send a text message from Outlook to a cell phone? Yes, as long as the phone supports SMS (short message service). Which most phones do. All you need is the email address. :)

The major cellular companies assign an email address of [10 digit phone number]@cellular_carrier.com and you can use this to send short messages to a cell phone (messages longer than 160 characters may be split into multiple messages of 160 char each). If it's a camera phone, you can send jpg's to the phone. I do this to email phone numbers, flight numbers, addresses, and pictures (for contacts) to my phone.

If you don't know the correct email domain to use, check the carriers website or contact their customer service. I have a list of domains for US carriers at http://www.slipstick.com/outlook/smscell.htm. If you don't know the carrier, enter the 10-digit number at http://www.phonenumber.com/reverse-phone.

If you don't know the domain or the carrier doesn't support emailed SMS, there are SMS add-ins you can use with Outlook. These typically require just the 10-digit phone number and use an SMS gateway, not your SMTP server, to send the message. A list of SMS add-ins is found at http://www.slipstick.com/addins/pager.htm#personal. These are usually text only, no attachments.

Note, the cellular subscriber may be charged a per-message fee.