What ? Dude Messenger is dead, all your contacts will merge to Skype, is that too difficult for you to understand ? -.-
You can acess Outlook.com on your internet explorer RT device, just like i do on my laptop, although i also use mail app, its pretty neat since i know when i receive a mail even if im watching movies or series.
Basically you will only need to use Skype, if you log with you Microsoft account your Messenger Friends that update to Skype will be there aswell. Dont Worry, its as easy as 2+2.
On RT and Pro:
RT is a simple Tablet, just like the Ipad you can only do basic things on it like read newspapers, surf the web, get some apps.
Pro is a full laptop/tablet all in one - You can do all like in a normal Windows 8 Pc, includes playing games like Diablo 3 or Call of Duty.
How is this a mess ? Maybe for 80s years old people i have to agree.