A few hours ago, I stumbled upon this site called Connectotel. The company offers a free SMS to Skype service that allows GSM users to send SMS to a Skype user. Though the company doesn’t charge anything for this service, regular SMS rates still apply.
I think it’s cool because I can send a reply to my Skype friends who use Skype to text me. If you know about any other similar service, please let me know. :)