Burn Notice is Charlie.

I think the suggestion is that the voice overs were the stories for Charlie, not necessarily the details behind them.

The VO with Carla wasn't the same kind of VO as the others. For one thing, you see Michael actually talking, so it doesn't really even qualify as a VO. You just get fooled into thinking he's doing a VO because of the tone...we think we're finally seeing one. We're wrong.

I think the Voice Overs turning out to be bits of narration in the stories he's telling Charlie was a brilliant way to wrap the whole thing up, especially if you recall the Burt Reynolds' episode (Past & Future Tense) in which he says, "In the end, all you really have are your stories". Michael has a lot of stories, and if I were growing up with him, I'd want to hear them all. Not to mention, I'm guessing with a father figure like Michael, Charlie Westen is going to grow up to be a pretty capable person and would appreciate hearing them.

Besides nobody's saying he's telling a little kid these stories. He asks Fi what he should tell Charlie, "when he's older". With that many stories, it could take years to get through them all.

By the time these VOs are taking place, the Westens are living new lives with new identities. It would make sense that Charlie would eventually want to know where he came from. It would also explain why Michael would need to recount the experiences that got them there in a realistic enough way that Charlie would understood why the truth could never get out. I also like another thing the narration accomplishes; that he really was able to get out of the spy game for good. That's also implied at the end when he's explaining how a spy's fate is that you're a spy until you're dead, and then continues to say, but one thing spies aren't good at, is accepting fate. So in the end, not only is he not dead, but he's able to leave the spy game anyway.

I don't know if talking to Charlie was the plan from the beginning, but if it wasn't, the writers sure were good at tying it all up in a nice bow. On the other hand, if you believe Jeffrey Donovan, who once said that Matt Nix always knew how the show would end, he just didn't know how they'd get there, then he may very well have known all along that Michael was talking to a loved one, --not some classroom in the CIA or some imaginary audience in his head. I'm guessing the latter is true, because I know writers in general find voice over narration to be a lazy way to tell a story. But that's not the case in Burn Notice. The show would have been okay without narration. The VOs weren't there as a cheat factor, they were an actual character in the show. Michael's future self reflecting on his past.