Just to add to Amy's comment, FrontlineSMS doesn't support incoming SMS through the Clickatell service right now, but does with IntelliSMS. You do, however, have to pay them for that service so you'll need to work out the costs and decide if it's worth it for you. (Details should be on the IntelliSMS website). Many users use a web service to send outgoing messages, and a GSM modem with a local SIM card to receive. It sounds like you're not too keen on going that route, but it's worth considering. Of course, in the US you pay to receive messages so this makes it even more of a challenge for you.
Great to hear back from you especially that you're interested in developing your use of SMS. Can I recommend that as a starting point you try downloading the current version of FrontlineSMS from here and let me know how you get on? We've got some great quotes from radio stations who have been using the software on the bottom of this page and we try to update the :Radio blog regularly with different case studies. Let me know if you want to learn more or perhaps arrange to have a chat?
I've heard from plenty of people in the same boat as you and its a great benefit to have internet access. I'd advise that you check out the help pages on internet services which you can find here which offer tips on setting up Clickatell and IntelliSMS which are both directly configurable through the FrontlineSMS interface.
To start, click on SMS Internet Service Settings in the Settings menu in FrontlineSMS. If you have existing accounts set-up, they will appear on the next screen. If you have no accounts set-up yet, click 'New' on the screen to give you an option to set-up an account. Then you need to set up an IntelliSMS account or a Clickatell API Account. Please note for these services to work they will require a working internet connection.
Enter the details you receive into FrontlineSMS's Account Configuration screen. Once this is done, the Clickatell or IntelliSMS account should appear on the FrontlineSMS Phones tab even if it cannot connect. It might be handy to set the "sender number" as it'll make messages sent via the internet service appear as if they're sent by the modem. If you have an active (connected) Clickatell or IntelliSMS account, then FrontlineSMS will automatically use that because it's quicker and usually cheaper, and ignore the other phones attached.
If you need further support, you can check out some of our users' experience with SMS internet services on the forum. You can find two particularly useful threads here and here.
Welcome to the forum. I was interested to read you are working with Radio Baha'i. You may already know that we are working on FrontlineSMS:Radio - a tailored version of the software optimised for radio DJs. Its currently in a closed beta with 3 stations but we will include more stations early next year. For more information, checkout http://radio.frontlinesms.com.
I am interested to know how you radio station interacts with the audience if they have limited internet. How many SMS do you receive a day? Is there a particular show which promotes more interaction?