@Ron Eve and others - re Card pre-authorisation
"Flames aplenty. Facts a few" said Ron. Well, it might have helped his case if he'd been a bit more clued up himself - indeed, there appears to be widespread confusion here so let's introduce some facts...
What appears to have happened in the case of MobileMe is that Apple has *pre-authorised* cards for the sum of £121 - a pre-authorisation is not the same as the money actually being taken, instead what happens is that the bank or credit card company reserves the requested amount - a typical application of this happening is when you book into a hotel the system will ringfence a certain sum as a deposit, and anything up to that sum can then be charged onto that account if you then do a runner (even if you cancel your card). On a less dramatic level, it can help to ensure that a hotel customer will have enough dosh in their account/ enough credit available to actually pay the bill when they leave (though this isn't a guarantee as other offline transactions may have subsequently been billed to the account, but let's keep it simple!).
What Apple and countless other companies do is utilise this facility for a different purpose - that of ensuring that the card details submitted by users (or potential customers) are valid, and - as the article states - they do this by pre-authorising the card for an amount "typically the equivalent of one US dollar ($1USD)" (the text from the MobileMe T&C's actually just uses the word "authorization" but I'm certain that what they actually do is a pre-authorisation - they're just keeping the language simple so as not to get too technical).
Or at least Apple should have pre-authorised the cards for US$1 - however it appears that they've managed to pre-authorise them for £121 - which at around US$240, somewhat more than the promised US$1.
This thus means that people who used debit cards can't get access to that £121 in their bank account, whilst credit card users will find that £121 of their available credit has disappeared. A potential problem for both sets of people, though debit card users are more likely to end up in trouble because of this if they don't have a lot of slack with regards to their bank account (i.e. no overdraft facility, or just as likely not enough of an overdraft left!). This could mean that direct debit payments get returned, which may well lead to charges being imposed by both the bank and the company collecting the payment.
In essence, Apple (or indeed anyone) screwing up like this entails some of their customers getting screwed up, and as such it's a surefire way to royally piss people off.
But hold on, its not Apple's fault, it's their customers fault... apparently.