Download PSO:Blue Burst for free, (register a hunter's license there while you're at it

), and then get a OGG to Mp3 converter. You can then convert the songs from the OGG format to Mp3, and you should be able to listen to them all (Including Burning Rangers) easily. Since you'll be downloading it, shameless advertising isn't amiss: You can also use this method to throw in your own songs while playing PSO:BB, and they'll work just like the BGM normally would. In short: If you're going to download PSO:BB for the songs, at least register an account for one month until PSU hits.
There are also more classical compositions of
Can still see the light - One includes a full Orchestra and can be found on the original PSO soundtrack. The next isn't really the same song, but is a very nice piano composition titled
Leavin' Flow. (This plays when you defeat Falz with a dark weapon and go back to see Rico.)
Finally, there are two other versions of
Can Still See the light that are done on the piano. The first is Disk Vol.7 from gallons shop, and is a nice (though depressing) instrumental. The second is my personal favorite, and is performed by Kiminori Atsuta on the Sega Piano Nocturne Album. Definitely do some searching for this one, it's well worth it.