I just joined Web Master World because I have exactly the same question!
I successfully created my Byethost hosting account and my Namecheap domain.
My website is up and running on my free generic Byethost web URL that I got for free. I then 'added' my domain in my Byethost account, got the 5 Nameservers it gave me, logged into my namecheap account, and put the nameservers into my domain name DNS settings. However my website still does not work. It seems I followed all the instructions and waited as long as I should have (2 days) but it still didn't work.
Did this happen to anyone else with Byethost and Namecheap?
I would appreciate it so much if someone could help me!