UK data SIM?
 

I currently have a Nokia N95 with a O2 contract SIM - I also pay £7 (or whatever it is) for 'unlimited' data.

Very soon, I will will have an iPAQ 6915. In general, I will still use my N95 for web browsing and checking emails, but every so often, I might want to use my iPAQ.

On the face it, the best way to go is to get a PAYG card - O2 are the cheapest at £3 per MB.

Any thoughts?

tmobile are cheaper....£1. per day max or you can buy a w&w pack i think for £7. or is it a fiver a week something like that

I agree - T-Mobile is the way to go. Maximum 40 megabytes per day, strictly speaking, although this is a soft limit.

Orange isn't too bad either, 1 pound for 15 MB.

Yep, TMO is the way to go (I'm using it right now to write this!) but there are a couple of caveats. 1) It uses a proxy server that severely compresses JPEG images; 2) there is evidently a list of restricted sites that you can't go to unless you register your credit card; 3) the terms and conditions specifically exclude laptop use, though it will work (VoIP and filesharing are also specifically excluded and probably blocked). The soft limit is calculated on a monthly basis, but please don't abuse it for the sake of other users (like, uh, me).

After your 10 days of free browsing are up, you can purchase a five-day pass for 2.50 that offers the same thing (half the usual price).

Vodafone also has a one-pound cap, but starts charging again once your use exceeds 15 megabytes (at, I think, 3 pounds per MB).

Virgin rips you off -- 5 pounds per MB.

Yes, T-Mobile seems to be the best overall offer, however it may not be for me.

I only really intend to use the iPAQ for email. Having looked through my inbox, the average mail is probably about 3 or 4kb. If I select the option to download headers, these are only about 1kb.

I generally receive about 10-15 emails a day that I need to actually read and do anything with, so assuming that I open them all, I will only use perhaps no more than 50kb for reading, and say the same for sending.

Perhaps something like O2 at £3 per MB or Orange at £1.18 per MB might work out cheaper. Or am I missing something?

Oh yes - it's not much use anyway at the moment as Pocket Outlook (or whatever it's called) doesn't seem to like IMAP from Google Mail!