Just set the TalkTalk account up on your Macbook Pro as you would any other email account.
What happens next is up to you. if you are still using the Windows PC then every time you open Outlook on it it will attempt to download emails from your TalkTalk email account. If you don't want that to happen, then it is indeed best to delete the account from Outlook in that PC. But that means all the emails you have stored in Outlook will be lost, so be sure to back those up first.
If you are getting rid of the PC then you may want to delete the account on it or delete Outlook anyway to preserve your ID and any personal emails, but in any case I would wipe the PC hard drive clean anyway before passing it on or getting rid of it.
Mark
I have bought a Macbook pro and wish to retain my talktalk.net address. I use Outlook 2003 on my PC. Do I need to remove the address from Outlook so that it can be accessed by the Mac?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic