|Port 80 will do fine, that is the default port for HTTP. There are times when you might need to change it but if it works leave it as it is.|
You can use a name by using a Dynamic DNS Service like this http://www.dyndns.com/
You get a domain name from them and they link it to your IP address. You run a small application on your PC which constantly monitors your IP address and when it changes, contacts this service which updates the DNS record. Some routers have this facility built in under Dynamic DNS. All you need do is enter the details of the service.
This service is free for home users and you can have up to 6 domain names but they can only be used with this service.