Three announced probably the most compelling price plans for the iPhone 4, but there was an issue - they didn't have free stock of the phones. 

Starting today, Three now have stock and you can buy both versions in Three stores, or the 32gb version online from www.three.co.uk

£30 a month gets you 500 mins and 5000 texts, as well as 1gb data and 5000 3 to 3 minutes, which is equivalent to most other networks £35 plans. 

If 1gb of data isn't enough, you can also add further 2gb for an extra £5. 

Link - Three