I bought a domain from godaddy and i need to map it to my raspberry pi. I tried to ask at&t (my isp) about it and they did nothing. Can i have some help plz? i'm new to networking and need to learn.
You will probably have to sign up with a dynamic DNS service. Domain names have to map to a static IP address, but home users generally get a dynamic IP address from their ISP unless they are forking over some extra $$. Dynamic DNS services have you periodically run a utility on one of your home computers (I think ddclient would work on the Pi) that updates their servers when your IP address changes. You would have to basically set your godaddy domain to redirect to the dynamic dns service which would then provide the address it has stored for you. Unfortunately this isn't ideal because while you will be able to access the Pi using the domain name you purchased, it will only be indirectly. So for example when you go to mysuperdomain.net the browser will be redirected to rpi.x64.me and all URLs in the address bar will show up relative to the latter instead of the one you paid for. Don't forget you'll also have to forward whatever ports your Pi needs open on your router as well.
Alternatively, you could do something fancy like rent a VPS from somewhere like DigitalOcean, and have your domain point to that server. Then tunnel the ports from your pi to that server over SSH or VPN and direct requests through there... Or use it to set up your own DNS server and figure out how to do your own dynamic DNS so the Pi would be a host on your domain. That seems like it would be pretty difficult, though.
I don't know of anywhere that would let you directly update the records for your domain with a dynamic dns client, and that would kinda suck anyway because changes to the DNS records would take a while to propagate.
Hope that helps!