Just make the account with the coin name and voilà. You reserved your name.
^^^ That is to reserve the username in the forum.
After that, you should head over to
the altcoin announcements section, and make a
pre-announcement of your coin.
Update the thread every now and then and you should be good.
I suggest you ninja launch keep all name secret till you have a working coin on test-net and ready to launch. Registered trademarks are a good idea but are costly and time consuming, also they come with no guarantee that a thief won't come copy your name or take your idea. Look at Peercoin where the other DEV ran off and created Primecoin, or with us when we pre-ann
here our name was jacked with a basic scrypt copy before we could even launch. Loose lips sink ships.