background process with ruby on rails

Here is what I'm trying to do. (not sure how to do steps 2 and 3)

1. User uploads a file to server ( i know how to do this ) 2. once uploaded a background process needs to be run on the file (could take a minute of 2 to complete) 3. display the results of the processing back to the user. (either as a statically created file or somehow returning some results to rails)

If possible to have ajax thing showing progress that would be nice, but not required.

Any ideas where to even start with this? Pointers to documention or a sample code would be ideal? I'm sure someone has done this before.

thanks j