OK....I'm not an expert. I've installed custom firmware often in my 1000 and 2000 models. 3000's I have never messed with - due to problems installing PERMANENT custom firmware. My understanding, however, is that is IS possible to install what they call LITE custome firmware for the 3000 units that have installed firmware 6.60. I haven't tried it, so I can't vouch for it. But you can try it: http://www.pspmod.com/forums/downloads.php?do=file&id=250
-Your other option, of course, would be to pick up a cheap 1000 or 2000 unit on Ebay or wherever, and then you have the option to install a permanent custom firmware.
-Hope this is helpful.