Three are currently doing a free sim offer,
U can also get £10 credit if you port in a number.
Will only work in an unlocked 3g handset.
Sim Only - Terms & Conditions
Offer available until 30th November 2008 and limited to 2 Sims per customer. Texts charged at your normal network rate. Sim is for use in either a 3 handset or an unlocked 3G handset. Stretch bundles last 30 days. �10 credit applies to new PAYG customers only and will be applied to account 7 days after the customer�s number has successfully been transferred to 3. Inclusive calls from the UK to standard rate landlines beginning 01, 02, 03 and UK mobiles and texts sent in the UK to standard UK mobiles. Maximum charge for NTS numbers (beginning 08) will be 15p connection and 15p per minute. Terms apply. Delivery within 30 days. See three.co.uk