many countries have that type of api to send free SMS..

The realistic perspective on SMS is -->
how much outward-traffic SMS does one expect from their site ?
1) go to a commercial SMS host or
2) use email gateways -- in which case you will be thottled by your (shared/VPS) HOST's hit  rates - if they do not like your usage --you get shut down. If you'be got a dedicated server,  you are okay ;-)

SMS is enabled now in Westors Elgg Manager, almost I forgot to post it here :-)

http://community.elgg.org/pg/plugins/release/616305/developer/westor/westors-elgg-manager

Please read the release notes and the first comment.

Here's an interesting article (from Big Blue) on SMS - interesting and more so since the underlying technology is at least 13 years old ;-) when I first coded my SMS server on the good ole zOS ;)

might wanna add a link to the article D?

oooppppsszzz lolz ;-)

http://www.ibm.com/developerworks/web/library/mo-sms-web/index.html?cmp=dw&cpb=dwwdv&ct=dwnew&cr=dwnen&ccy=zz&csr=111011

funny thing abt that 1st sms server was that we tested by sending funny strange sms's to ppl we knew on the project teams and they never found out what was going on !;-X hahahahhhh ... ;-P