Not quite the Skrulls, but not quite not the Skrulls either.  Loki’s army will be the Chitauri.  The Chitauri are an alternate version of the Skrulls from Marvel’s Ultimate version of their characters.  So, it is but it isn’t.  It is possible the the trademark to the Skrulls is locked up in the Fantastic Four movie rights, and thus not currently available to the Avengers and Marvel Studios.  Although word is that the Fantastic Four movie license will revert back to Marvel very soon.