I made a spreadsheet for a comparison between tariff/carriers. If you are interested I'll keep this up with further updates as soon they are announced. Update 19th June 2010 - 13:45 O2: tariffs and handset price. Vodafone: tariffs and handset price confirmed. Orange: tariffs and handset confirmed. In addition: O2 offers Data Bolt-On from October; £5 for 500MB, £10 for 1GB. Orange and Vodafone offers tethering.