Slam, could you tell us what equipment you have in your church at present? If we know that then we can make some suggestions as to how to get the sound from your system to a tape. (I take it you're referring to an audio cassette tape.) Do you want the whole service or just the sermon?
If you are new to all this stuff and want a really simple method, just get a portable cassette deck that has a built-in microphone (i.e. can record by itself), start it up at the beginning of the service and stop it at the end. Just keep it towards the front of the church where the sound is clearest and there is minimal recording noise. Make sure there's enough tape in there and that it's set to switch sides so that if you have say a 45 minute tape you'll have up to 90 minutes of recording time. While the quality will be poor, your member in Afghanistan will be able to hear enough to appreciate the service.
If you want to get better sound of course then you need to tap into your sound system as described above.
