The URL you listed above is an option but i was thinking that you wanted to tie it in to functionality on your site. Third party services like this envolve uploading you VERY personal customer mobile numbers on to their DBs. If you could setup a simple SMS gateway connect to a global aggregator like IPX (www[.]ericsson[.]com/ourportfolio/ipx) you would have ful control on your data and a real flexible solution moving forward. Mobile is the future so a little investment in time and money now could mean a lot to your long term mobile strategy.
I see in your original post that your looking for a cheap option so sorry if my posts in your thread are way off the mark
