[Staffslug] Duplicate SIM Cards

Hi all, I was just wondering if anyone knew much about this subject as Google is showing me forum posts that haven't been updated since 2006. Say I have multiple devices in my home that use a SIM to provide for example,PDA, Car phone, 3G Door Bell... I don't want to pay a contract for each one and would like to avoid PAYG due to having to top them up seperately etc (and having to remember to do so). Basically, I'd like to take out a cheap £20 contract which offers unlimited texts.. and then put a SIM card in each device which corresponds to this one account. I've heard about Orange Single Number and Vodafone MultiSIM - but they are either costly or only available to businesses. I would have thought it was possible to simply duplicate/clone a SIM? And surely if it's my own SIM it isn't illegal? (Unless of course the SIM remains the property of the network operator - I'm not sure if that's how they work these days). So yeah, any info on this would be great! Adam