No, that is the naming scheme Comcast uses. You could create a secondary account with the name you want to use and copy all your stuff to the other account. But is it really worth it? it will still have the home.comcast.net.
One way would be to create a comcast account with a friendly name but you'd still have home.comcast.net, as bethkatz pointed out.
The other way is to get a domain name from someplace like GoDaddy. Unfortunately Comcast is lame when it comes to some things and this is one of them. You can't assign the domain name to your comcast PWP but you can get GoDaddy to redirect to your account. There are two ways to do that, neither is ideal.
One way is where GoDaddy uses frames to include your web page into an empty frame of a page hosted by GoDaddy. It works, but the downside is the URL never changes so if you Refresh your browser you are sent back to your home page.
The other way is to have GoDaddy redirect your fancy domain name to your Comcast PWP. Everything works OK except that the address bar shows the Comcast URL. You can refresh and people can bookmark a page. If you decide to move your web site someplace else, you can do that and retrain your fancy domain name but peoples' bookmarks will fail. That is the method I use and I'm happy with my trade off with the devil. I use my fancy domain name when I give people my web site address, and that's good enough for me.