I’m not sure if I was wrong yesterday or whether the O2 site has changed but it seems it is possible to pre-order an pad compatible Micro SIM from O2 if you follow this link.
Looking on the front of the O2 site I’m still not spotting an obvious link to that page – I stumbled on it via Apple’s UK site – and my call to O2 yesterday resulted in being told to call back on Friday so at least some O2 are apparently unaware about the web form.
Anyhow, while O2’s 3G network isn’t always as robust as I’d like, the per day plan of 500MB for £2 promises better value for money than anything their rivals have currently announced.