There is no “Create new account” link on the list account page. Here I found that the reason is some kind if migration… (last post on the linked page).
Does anyone know how long will take this migration, and when I will be able to create new account ?
Visit www.000webhost.com and click create new account, sign up using a new email or one you’ve not previously used with 000webhost.
James, thanks a lot. Does it mean that in the future I will need to log in twice - one for my old site (different email), and than log out and login again for my new account?
Yeah will do in the meantime 
Keep regular backups!