Phone interviews are very common; it's called "pre-screening" where they'll ask you a few questions to see if you fit the basic requirements and then if you do, they'll bring you in.
As for what they can ask former employers, it varies from state to state. However, in general, most times you'll be transferred to HR. The only info HR will give out is: name, title, start date, end date. In other words, all they will do is verify that you did work for them. That's it. From their professional perspective, the last thing they want is for you to come back later and sue them because they said something negative about you to a prospective employer. Most of them aren't Catbert; they hope you'll find another job.
One thing you should definitely do is to contact a former co-worker from the company that terminated you (preferably someone who is familiar with your work) and ask them to be a reference. Also, give the prospective employer references from previous companies where you weren't terminated. If you have 3 good references and one bad one (or one who won't give any info at all), usually the good will outweigh the bad. One very very important thing you must do is contact the people who you want to use as references, and make sure they agree to do it. Also give them a heads-up if you think a specific employer might contact them for a reference - that's what I do.
I know this might seem really awkward, but if it were me, I think I would have asked them, as they terminated me, what kind of a reference I could expect, or how they think it might affect my future employment. Since you weren't able to do that, you might contact your former employer and tell them that you're worried about finding another job after having been fired. You might be able to come to some kind of agreement with them about what they will or will not say when called by a prospective employer. They might be willing to provide a letter (on their letterhead) "To Whom it Might Concern" that lists what your job title was, start and end dates, and what your job duties were. The letter wouldn't give a reason why you left or an assessment of your performance.
Good luck and keep us posted on how your job search progresses!