With the demise of the muxtape service, a new option has popped up - the ability to run your own version with a PHP application called OpenTape. Lifehacker has posted a guide to getting this software set up and working.
Beloved music playlist hosting service Muxtape's gone offline to "sort out a problem with the RIAA," but if you've got some web server space, you can host, stream, and share your own digital music mixes Muxtape-style with newly-launched PHP web application Opentape.
It's not a direct copy, but it's pretty close (and pretty easy to get up and running). It'd PHP5 only, so if you're still living in the past and only have PHP4, you're out of luck. Their guide shows a sample installation on a Windows machine, but its not much of a stretch to follow along on a unix-based machine. You'll also need the curl extension to get some parts of it working - it's not required, though. They have a work-around for that too.