Switching from Sky to FTTC provider

I�m currently with Sky for line rental, calls and broadband, now FTTC has become available in my area I�m considering switching providers (maybe BT) but have a few questions before I do.

1: Will I have to switch back to BT for my line rental and calls? If so how easy is this and will there be any costs involved?

2: Will I be able to keep my phone number?

I currently have my Mac code so the broadband side of things should be straight forward or are there any pitfalls I should know about and look out for?

Mod�s if this post is more suited in another forum please move.
Thanks
Jimmy

BTW I'm not with eclipse as below, will change it later