I think the sinopsis (did I spell that right?) (basic plot of story) is that twilight accidently turns into an alicorn, and she tries to turn herself back. Surely they wouldn't be stupid enough to have her transfrom into an alicorn, with NO build up what so ever mind you. So..I kinda doubt the transformation is permenant.

This is something that I've wondered for a while as well.  A few months ago (late November/December), when it was all rumors, I hadn't really thought about it.  Now a days, everyone seems to be scared sh-tless about it like it was officially announced or something.

It has been confirmed that she will become an Alicorn, and it has also been confirmed that it will be permanent.

  On 2013-01-31 at 2:34 AM, Stormwing said:

and it has also been confirmed that it will be permanent.

Creditable links or it didn't happen.

  On 2013-01-31 at 10:09 AM, ~Chaotic Discord~ said:

Creditable links or it didn't happen.

http://family-room.ew.com/2013/01/29/my-little-pony-friendship-is-magic-exclusive-twilight-princess/

This.

 “I don’t think becoming a princess really changes her; I think it’s going to introduce some new challenges for her.”

This quote quite heavily implies that it will be long term if not permanent.

The Hub will celebrate the mane event with a nine-episode MLP marathon on Feb. 16 beginning at 6 a.m. ET, followed by the coronation episode itself at 10:30 a.m. The network is also throwing a Coronation Concert in Los Angeles on Feb. 9, hosted (appropriately enough) by newly crowned Miss America Malory Hagan. Olympic gold medalist Carmelita Jeter will be on hand as well.

No, Twilight is NOT an alicorn. (Come on, guys.) However, she will BECOME an alicorn in the season finale. Basically, she writes her own magic, and since doing so is a great accomplishment for a unicorn, she is granted the title of "Princess".