The Overcaster Family has already updated their Mac Napster client, Rapster, after releasing the debut version just last week . Rapster 1.0b2 allows Mac users to share MP3 files with other users of Napster compatible software, allowing nearly limitless access to a full library of MP3 encoded songs. According to Overcaster:
Rapster 1.0b2 is out with many new features, such as download resume, advanced search and firewall downloads (this should eliminate the "This download is not implemented yet" error).
Rapster is the all-new, fully featured, unofficial Napster client for the MacOS. It already supports file downloads (soon resumable download(s)), searching, "Hotlists" and a complete chat and private message system. Rapster also allows you to use your previously registered Napster account or register a new one.
With Rapster you can search for your favorite music and artists, chat with other users and, of course, download tons of MP3. Soon you'll be able to share your MP3 files over with thousands of Rapster users!
Napster is a MP3 exchange protocol, also featuring chat and private messages system. It allows anyone with the server application to share MP3 files with other users. This exchange capability works just like FTP, and the chat/private messages are very similar to IRC.