Yes it is.  The reason it will be "Castle in the Sky" rather than

 >"Laputa:  Castle in the Sky" (or variations thereof) is because it has to
 >do with Laputa meaning something different in another language.
 
 	To be a little less polite about it, laputa can be translated as la puta.
 In spanish, this means 'the whore' or 'a whore'.
 

One wonders if Miyazaki is aware that a nonsense word plucked at random for a
name makes one of his more famous works an obcene request/phrase in several
major countries.

I find that VERY amusing. In my own sick sick way.

-Mercutio
"A plague 'a both your houses!"