Hi. Welcome to AcidMods.
About your ideas, these both have been done. The music responding lights are called sound reactive LEDs, and can be wired up using an 2n2222 NPN transistor or connecting the LEDs direct contact. The ones turned on and off by a switch are normally turned on and off by the hold switch, and for the PSP fat, sometimes the WiFi switch.
There are many great themes on the internet. I recommend GirlGamers
. Also, a Pandora battery is basically a modified battery used to put CFW onto the PSP, in conjunction with the Magic Memory Stick. And you could probably get a jukebox skin from DecalGirl, and if they haven't got one you can have your own custom ones made online.
And don't worry about being new; everybody on AcidMods started as a Guppy (apart from admin
), and eventually you will probably know a lot in this field.