The easiest thing to do is to do the timing in Premiere Pro. You can even add some motion by scaling or repositioning the pictures. If you insist in doing the entire project in AE you can preview the audio by using the . key on the numeric keypad and then tap the * in time to the beat to put markers on the audio track.
If this is your first real project of this type I'd just load all the photos in Premiere Pro, load up the audio track, reveal the waveform and start by just cutting the photos to the beat. You should be able to see what's going on in real time. When you get the basis edit done then you can go back and add transitions or move the project into AE to do some fancy moves.
Depending on the music you may be able to figure out how many beats per minute there are in the song and then just load up all of the images in order, trim them to the average length of a phrase and then sequence the layers. The real trick to any of this is to get a cuts only version done before you try and do anything fancy with the images.
Is there any step-by-step tutorial for this?
You can use this technique to cue up the images in order and give them all the same length. I would not choose to overlap and add transitions at this point.
Then you just adjust the edits and do whatever you want as transitions.
This is really basic stuff. Have you ever use AE or Premiere Pro before?
If you want to use AE it's a lot more difficult but if you start with Premiere and get the timing down then you can import the Premiere Pro sequence as a comp in AE and fine tune things.
One more hint. Make sure that your images are the fight size for video. If you take a bunch of 20 Megapixel images and drop them in the Premiere Pro timeline things are going to slow way down. If you plan to move in on the photos then you should plan for the "close-up" section of the image to be the same width ad your video (1920). If you are not going to move in on the images then you should make them just slightly larger than the comp. You can use Lightroom or Photoshop to batch the images for the project.
There are a lot of other subtle things that go into really good editing to music. Depending on the size of the screen and the composition of the shot and the tempo and feeling in the music you may need to have the shots enter frame a few frames ahead of the beat and other times a few frames behind the beat. You can't judge this accurately unless you do a full screen playback. If the video is going to be projected on a very large screen like at the prom, then you'll probably want to slow down the cuts even more. Most of the time just cutting on the beat is pretty easy and works pretty well.
One last hint. Try and match up shots with musical phrases. That usually means at least 4 bars at a time. You seldom want a shot to last less than one full bar. I hope this helps.