If you have an AT&T Wireless, Bell Canada/Bell Mobility, Cellular One,
Cingular, Cricket, Sprint PCS, SkyTel, or T-Mobile cell phone or pager, and you
want the ability to send SMS messages to it via a command-line utility, this is
what you need. All this program requires is a computer with a baseline Perl 5.x
installation and web access. NO EXTRA PERL MODULES REQUIRED!

How does it work?
SendSMS connects to your service provider's web page and pretends to submit a
form to their 'Instant Messaging' web page. Currently, AT&T Wireless, Bell
Canada/Bell Mobility, Cellular One, Cingular, Cricket, SkyTel, Sprint PCS, and
T-Mobile are supported. Users are encouraged to modify the provided templates to
add support for any providers who are currently unsupported.

Other Service Providers
If you are interested in supporting another service provider please try to
modify sendSMS on your own. It is not hard at all. Instructions and examples are
included in the code, and if you're familiar with the site you're porting to, it
takes about 15 minutes. If you get sendSMS working with any other providers' web
sites, please email Paul Kreiner [deacon at thedeacon.org] and/or the port
maintainer a patch so it can be added to the next release.

WWW: http://caspian.dotconf.net/menu/Software/SendSMS/