From the author of ViaHTTP, POPThing (freeware) is a small application that allows you to check standard POP email accounts for new messages; it allows you to delete messages as well. It's nicely designed, and extremely easy to set up. I only wish that it could check all accounts automatically upon launching.
Can't find what you're looking for? Try a search:
Also, if you have an older Mac, be sure to check out the "Classic" applications page for more options.
Finally, take a look at ALEMIA if you think you know that name of an application, but aren't quite sure.
No, I don't accept reviews anymore for these older applications. With the creation of this page in the Orchard's late 2005 redesign, I only accept reviews for currently-developed applications that work on Mac OS X (or later....whatever that might be!!).