MacSOUP is an offline reader for Macintosh. It handles news andmail (but it can optionally interface to Eudora or Claris Emailer, if you prefer to use that for all your mail). It works either with a Unix shell account (in conjunction with uqwk), or with a TCP/IP connection (MacTCP or Open Transport). Can (optionally) fetch only article headers in a first pass; lets you select which articles you actually want to download. This option can be set separately for every group you read.
Check in at ftp://ftp.zit.th-darmstadt.de/pub/Macintosh/MacSOUP for the latest version. And remember that MacSOUP is shareware, so if you use it, pay up!