I would call and let them know: 1) that you have applied and that you are interested in what the "next steps" may be. 2) Let them know that you expected to receive an e-mail to complete a web-based interview and such e-mail has not yet been received. And 3) Express enthusiasm for the position.
Every time I call, I get told to wait as it could take up to 6 months for them to get to me. And I think the web-based interview email are only for people that pretty much got the job - they don't send that to everyone, I don't think. I even considered the college program, after all this wait, but I just don't have time for that. I think if you call the casting center, only the receptionists answer the calls and give you general information that you already know. Wonder if there's a direct number to speak to one of the casting people :/