I thought I'd post some information I found useful.
In an earlier posting from "Big T", a strong magnet was used to retrieve a screw that was accidentally dropped into a dishwasher. The magnet was purchased at Wal-Mart's automotive department.
This advice was very useful, since I was able to retreive a dropped screw from my Maytag Dishwasher (Model MDB5100AWW).
Since the closest Wal-Mart is about 15 miles away, I instead went to pep boys and purchased a "Performance Tool" Pocket Magnetic Retriever (It was only $3.99).
This particular magnet was useful, primarily because dishwasher drain is difficult to get to. There are many dishwashing parts in the way, and the drain itself is protected by a circular 'catch' where the holes are about the size of a pinky nail.
It doesn't matter if you get this particular magnet or not - what matters is that you get a magnet that is short (so it can fit in this very cramped working area), telescopic (so you can extend it into the drain once you're able to fit it into the cramped area), and slightly flexible (so it can slightly bend to get to all areas in the drain). Although my magnet did not become stuck in the drain, I'd recommend approaching this job with a lot of patience - the last thing you'd want to do is to get the magnet stuck in the dishwashing drain.
I also purchased a swivel inspection mirror, but it proved not very useful because the drain catch holes are so small, and the area so cramped, that for all intensive purposes it is not possible to see into the drain. Although I do have to say that it gave me enough of an idea of how the drain was made to make my search a little more effective.
In any case, it took about 45 minutes of placing the magnet in all sorts of different positions to finally get that screw out. But hey, it saved me the cost and the time of having a repairman to come out.
For one, the head of the magnet was magnetic in almost all sides