I am currently using my phone with a Gmail account, but want to switch to an Outlook.com account. Does anybody know what will happen? Can I easily switch and what will happen to all the apps I paid for?
You're going to have to add an alias to your account.
Go to account.live.com, login, and on the left there is "Aliases". Add your outlook.com email to as an alias. Then all your purchases and such will be on both accounts with the same password.