I started my Nokia N900 contract 6 days ago.

£35 a month, 24 month contract.
600 minutes, 500MB internet, unlimited texts - all explicitly stated.

The guy in the shop also told me that I would be charged a maximum of 50p per day if I go over the download limit - that is effectively £15 a month extra for actual unlimited usage. (Unless they take other action to ensure fare use.)