phpBB update??

Hello all - i'm not very clued up at all in this area and after some advice. I have a phpBB board and not sure which version it is. If it is 2.0 i would like to up it to 3.0 but without losing my current content. Is this possible? Looking at php site i'm just going round in circles i'm afraid and not sure exactly what to do - so how do i know which i'm running? how do i update ? and one more question - is it possible to link to youtube clips in the latest version as that is the most common gripe coming from my members? thank you mike