Tesco have revamped their mobile site and are now offering iPhone 4 on pre-order http://direct.tesco.com/p/inc/specials/iphone/default.asp
Tesco are currently the best on price for the 3GS iPhone and are selling the 3GS 8GB for £449 on pay as you go with 12 months unlimited web and wi-fi. It will be interesting to see if they stick with this pricing especially as Apple will be selling the SIM free version of the 3GS at £419 from the 24th June.
Current Monthly rates on Tesco are
£20 a month 250 minutes Unlimited texts 12 Months + £222 for the 8GB 3GS
£35 a month 750 minutes Unlimited texts 12 Months + £100 for the 8GB 3GS
£45 a month Unlimited calls Unlimited texts 24 Months – Free