Well personally, I hope that Miley and Nick really are together, but Miley keeps giving us mixed signals.
Like on her Twitter, she talks about a rumor about Nick getting her a $75,000 promise ring is not true, and to not believe anything until she tweets it. That was tweeted yesterday (July 23rd) morning.
Today, July 24th, she tweeted this: "Thinking back on the good 'ol days"

Now, if I remember correctly, Nick did a little something like this too with flower pedals, but I think it was with his name. I forget, but if someone could find a picture of that it would be greatly appreciated (: