finally a thread i can answer some of!
the cd thing is kind of similar to windows in that you cant access the audio filesystems as you would for a normal data iso9660 cd. ie, you will need a cd program to play it as opposed to the usual 'mount /dev/hdc' command or whatever (if your cd drive is hdc). the best two ive found for this are the Gnome CD player (altho i use KDE) as KsCD isnt very good - or a xine player as xine supports cd playing. then , simply ensure xine knows the /dev location of your cd drive, and that your current user (and the users you want to play cd's) have access permissions to both the cd drive's /dev/hd? file, and to /dev/cdrom.
to do this, log in as root and type: 'chmod 766 /dev/cdrom' and 'chmod 766 /dev/hdc'
the speaker thing i dont know im afraid - i only use stereo!
firefox you simply install by downloading and unpacking into whatever directory u want to run it from. for example, if you download the firefox file into the /home/user/files/ directory, and you want it installed into the /usr/local/mozilla/firefox directory do the following:
OPEN A PROMPT.
'SU' so you are root user.
$ mkdir /usr/local/mozilla (make mozilla directory)
$ cd /usr/local/mozilla (change directory)
$ tar xfvz /home/user/files/FIREFOXFILE.tar.gz (unpack firefox file into current directory)
$ ln -s /usr/local/mozilla/firefox/firefox /usr/local/firefox
the final command creates a link so you can access it by simply typing 'firefox' at a prompt/'run' window.
AIM im not too sure, if i were you id use a compiled version of kopete 0.9.0, or gaim, but i prefer kopete. if you want help in compiling the source code let me know
good luck m8, and keep using linux!!