Ok, so here's the tutorial:

To start off, you have to turn your pictures into an image sequence.  To do this, click on the last picture in the animation.  Then, holding down shift, click the first one.  Then, right click on the first one and click rename

Rename it to something like 001 (1) or anim (1), just as long as it has some kind of name then a (1), it'll work.

You'll notice that all the other pictures now have the same name, but with a number in parenthesis after the name.

WARNING MAC USERS] this method might not work.  You'll have to manually rename everything (you can leave out the parentheses)

Ok, now that we have all that figured out, we can get working.

Open up After Effects and go to file>Import>File...

Now, double click on the first picture of your animation to open it.

What it did, is it recognized a pattern in the names of the files and basically made a 30 fps movie.

Drag it to the new comp thing.

Then, press Ctl+K to get the composition settings.  Set the duration to something pretty long.  (30 seconds worked for me, but you might want to do it a little longer.)

Right click on the video and choose Time>Enable Time Remapping

You'll notice that two little diamond things appear underneath your clip.  Zoom out and move one way off to the right.

Then, take the blue clip and stretch it a little past the diamond that you just slid.

Ok, so here's what we just did.  We imported the animation and slowed it down.  If you play it back (spacebar) you'll notice that it's really choppy and has a really REALLY low framerate. 
After Effects has an incredible tool called frame blending that basically takes a low-framerate movie and turns it into a 30-fps movie.

To turn it on, click the two buttons shown in the picture.  (the lower one with the line is actually gonna a be blank square.  when you click on it, it will have a diagonal dotted line.  Click on it one more time to get the smooth diagonal line.)

Ok, now at this point, i have to make a side note.  Sometimes frame blending doesn't really work like it should.  To prevent it, you need to have a high-framerate animation.  I'd say go for 20fps or higher. 

If you play it back now, it will be a slow motion 30 fps animation.  (well, not at first.  It has to render the preview, so it's gonna be slow.  Just let it go for a few frames and back up and play it again)

Ok, we're almost done.  Go to the Effects & Presets pannel and search for "CC Time Blend FX" (you might not have this effect if you're using a trial of After Effects)

Now drag the effect out to your animation.

Change the Instance from "Copy" to "Paste".

Drag it into the Render Queue and hit Render.  (you may want to play with the codecs first, though, by clicking on the "Lossless" thing.

Now import the movie that you just made back into After Effects and make a new comp.  Enable Time Remapping and drag the diamond to the left to speed it up.

If it doesn't work quite right, play with the Accumulation value.  (higher percentage will give you more motion blur and lower percentage will give you less.) 

I hope that wasn't too confusing.  As I said before, I hope to make a video tutorial for this in the future.  If you have and questions, please ask me, I'll be happy to help