DVD and CD media help

[aklaim]

I would like someone to help me out here and just explain what the difference is with DVD and CD media for example you can get DVD+RW and DVD-R, DVD+R etc and the same with CD media, what is the difference?

The reason I'm asking is because I've been offered a Philips 2.5x8 DVD+RW, 12x10x32 CD-RW I'm wanting to back up my PSX2 games but what do I do it on and will this unit do it?

It does say that it is a DVD-ReWriter and CD-ReWriter in one but what is the difference with all the media.

Please help if you can.