I'm wondering at what point in the anime series of Bleach do each of the movies occur? This way, when I watch the series I can stop at a specific point to watch the appropriate movie.
At the main story, the movies are never mentioned because they are like fillers and not canon to the main story. But it's possible to verify when they occur by some facts, by some situations that we saw in the movie:
The first movie, Memories of Nobody: Ichigo is able to use his bankai in the World of the Living, so it happens after the Bount Invasion arc and before the Arrancar one as he's still unable to use his hollow form. So, it is between episode 109 & 110.
The second movie, The DiamondDust Rebellion: Ikkaku use his bankai, so maybe it happens after the first invasion of Arrancars (the one defeated by Toshiro team) and before they entering in Hueco Mundo. In episodes, something near 138.
The third movie, Fade to Black: I think it happens nearly to The DiamondDust Rebellion during the Arrancar's fight, but before they entering in Hueco Mundo because Ichigo still uses the first form of his hollow mask:
The fourth movie, Hell Verse: In this movie, Ichigo uses the second form of his mask and transforms into his full hollow form, so he already fought Ulquiorra in Hueco Mundo and returned. Repeating, it's like a filler, after episode 299.