MadeWillis - 2:49 pm on May 17, 2010 (gmt 0)

at least it shows a long-tail searcher that we've got a lot of products similar to the one thing they were looking for

Maybe so, but once you setup the redirect that page disappears from the serps and you no longer show up for that long-tail search, thus you are not showing them anything.

I do agree about the phone calls though. Unless your customer service staff is good at upselling or recommending other products it could be costly. For the original site in question, almost all orders are placed online.

Obviously you would want to mention on that product page that the item is no longer available and that shoudl minimize the call volume.