I am on an O2 sim only contract at the moment. when I rang O2 they were very helpful and pointed me in the correct direction with usage etc.

Various people at work use them. You need an unlocked G1, obviously, have to manually put in the APN information (not a big deal) and the "fair use" limit is far lower than t-mobile's (which is 3Gb/month) but it works and their 3G is pretty good.

I heard back from one person saying he's going to wait a bit and the other hasn't replied so I've got an unlocked (both SIM unlocked, so you could use it with O2, and code unlocked, so you could put different software on it, change the boot image, etc) G1 I can sell you now. It's got CRB43, the most recent cupcake release, on it.

It's the one I was going to keep, though, so has the slip case and screen protector missing from the package (I used them on another phone) and I put one sticker on the back to differentiate it from other phones (easily removed if you want). Otherwise it's as new in perfect condition and it's the only one I could get to you this week. 150 quid (covers how much the phone cost me plus the unlock code... code unlocked G1s are generally going for a lot more).

It's at home, I'm afraid (had to rush out for a meeting this morning, forgot to pick it up).

You could come out to Blackhorse Road this evening or I could meet up with you somewhere tomorrow.

If you sign up for my t-mobile on their website and go to My unbilled usage -> Mobile data usage it will etll you how much you're using.

Of course it's by connection and doesn't seem to be summarised but it's there.

There's a data monitor app for android that'll tell you how much data you're using when, I'd assume there's something similar for the iPhone.