MS Internet News will decode UUEncoded, MIME-encoded, and BinHexed attachments. It will also automatically decode multi-part binaries.
1. Bring up the article with the attachment (or the first article in the series if it's a multi-part attachment).
2. Go to News--Extract Binary.
3. Internet News will begin downloading and decoding the attachment. Once that's done, it'll bring up a window asking where you want to save the file. Select a folder (or the Desktop) and you're set.