i'd suggest emailing support@phatnoise.com about the AAC thing... their site has definitely been screwy for quite a while, but they do respond to support emails... they fixed the PMM download forms last week after I emailed them.
btw, i've used vmware on linux with an xp guest for quite a while... exclusively to use PMM and yahoo music with a nomad zen xtra mp3 player... but vmware hasn't had full usb 2.0 support until the latest 6.0 beta. unfortunately, the 6.0 beta runs in debug mode for now... so it takes a performance hit from all the debug overhead... but the usb 2.0 support is great. I run samba on my linux box and store all of my mp3s in my linux home directory and map network drives from the XP guest... so that it's not wrapped up in the guest filesystem. i also tried the native vmware host internal shares method, but it was very unstable... better to just set up your linux box with samba.
edit: i'd love to start working on a PMM alternative for linux, but I want to avoid making it too specific to one window manager/desktop (GNOME, KDE, etc...), since I use WindowMaker 99% of the time. Juk (KDE app) has a nice tag editor. i haven't done any GUI programming, but I do have a couple of GTK+ and QT references that I've been meaning to look at for a while, and a CS degree under my belt
edit: sorry... just found the Phat4X linux PMM thread... i'll take a look at that...