Yes. I have applied for bunches. I got one which is my current job. What do you want to know? Sometimes I feel like internal interviews are just a formality. Most of the time the interviewer knows beforehand who they want to have the job, but have to interview people due to company and EOE policies.
I have - the job I have now was an internal transfer/promotion. For me, my interview was very informal and only happened because it had to. Also, I know at my company they would hire internal over external if it were between the two.