Both networks have previously announced they will be selling Apple's iPhone 4, but until now, we've not seen physical evidence. All that should change from tomorrow.T-Mobile announced on its own Twitter site that the network will have stock from tomorrow (Friday) and we've already heard that the network is calling back customers who have previously expressed an interest in the smartphone. The tariffs highlighted some time back didn't look all that tasty in comparison to other networks and all were two-year deals. Not ideal with Apple's track record of refreshing the line every year, but we have heard existing customers are being offered decent deals over the phone, so if you're already with T-Mobile and available for an upgrade, it might be a good time to talk.On the other hand, the 3 network's tariffs look very appealing in terms of both data allowance (1GB as standard) and call allowance, with a phone from free with a £45 contract. There are also sim-only deals starting at £15.Sadly, none of those 3 deals are available to order as yet and as a word of warning, 3 hasn't yet made it clear that the iPhone 4 will sell from tomorrrow on its site. But if you want one with 3, you might want to check the site early on Friday morning or drop into your local store first thing, as stock is likely to be as limited with 3 (and T-Mobile) as it is with all the other networks.