Dear Navaneeth,
when you registering domain www.xyz.com (what ever domain name) they will ask you where to point, so just give your existing Public IP address to them, then it will be browse your camera site.
1. Ask your local domain register for domain registration or any online register available, e.g.
http://www.godaddy.com
2. Give them your public IP where you are now hosting your IP cam.
3. They will do all that job, just sit back and see.
Thanks
RRobertsion