Can I use t mobile SIM card in iPhone 4?

T Mobile do unlimited internet for 30 days for £5 which seems to be the cheapest to me.
It's payg (pay as you go).Im getting it in a few days, it's unlocked (open to all networks).

Do you have any other SIM card suggestions for iPhone 4 that has UNLIMITED internet for £5 a month.

If its unlocked, it should work.

No. It will not charge if you do that. It is a design flaw