NLynx Systems, Inc. produces a whole line of Macintosh products for connecting Macs to IBM midrange machines over TCP/IP, including TCPAxcess, which provides AS/400 connectivity to Mac OS 6 - 9, and works under Mac OS X's "Classic" mode as well.
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!!).