Hi as for a sim card. They will virtualy give them away when you arrive. You can pick up a phone and card for as little as £10 in a supermarket.
Hi speed internet and landline will depend on where you are. cable networks will give you a whole package including TV at arround the £40 mark.
BT is about £25 a month i think for phone and internet package.
Speeds wil vary dependant on location.