I'm very new to PIC's and this list but have been using Linux since 2000 and having dual booted and used wine and/or cxoffice I am now using Vbox from Sun for running MS software. I run Slackware and the same vbox virtual machine is working fine on both 12.2 and current rc2
Yesterday I installed MPLAB and the PICKit2 software on my virtual machine. I don't know anything about MPLAP and programming PICs yet but the programmer is working fine and I can access the chip and power up the demo board.
AFAIC this the simplest way to go as most of the tutorials, etc. seem to focus on using windows and MPLAB and my guest system (XP) is somewhat portable as it is basicaly a big file xp.vdi which can be backed up on another drive should you want to repartition or just backup as a cron job. I just install vbox somewhere else and I can have it up and running again.
Note that there are other Linux aps if you know what your doing like PiKdev and GP-Utils (which has a Microchip approved MPLAB plugin) and also that there are two versions of Vbox for Linux. The open source version will not allow access to your usb ports, I have installed from VirtualBox-3.0.4-50677-Linux_x86.run, this will allow access to usb.