When I got my sim card from Tesco mobile in December for my iPhone 4, it said something about getting free access to BT openzone? Does anyone know how to get this because I've tried it before in an openzone area, but it just kept bringing me to a certain webpage and I basically gave up in the end because I didn't know how to connect to it.

Try downloading the iPhone BT Wi-Fi app you only need an email and password to sign into that. Otherwise contact Tesco and ask them.

Vodafone have a similar deal with BT. From the Open Zone website there is a drop down menu where you can log in using your Vodafone ID and Password. I haven't checked if there is a Tesco option. Alternatively, I have installed the 'my Vodafone' app, which logs you into open zone automatically when in range. Maybe Tesco has an app too.

Call Tesco and ask them, then post the answer here for other Tesco customers.