Very newb question but,i found a song but its a .rar file and wont play/open!? How can i open or change it??

Do you have Winrar or 7-Zip installed in your computer? If yes, then simply right-click the file and perform an "extract here" command. If you don't, then you know which programs you'll need to do this. Hope it helps.
EDIT: Oh, ho. Seems like you got your answer already in the requests forum. Meh, at least the effort was there. :)

I want to take advantage of the situation to troll a little, i hope you don't mind ^^

Please, please, PLEASE don't compress files in .rar... do it on zip, or 7z or tar.gz, or FREE, OPEN FORMATS that one can open from anywhere... last year i couldn't uncompress rar files with non standar characters in the inside files (like accents '^` or kanas/kanjis...) on linux... as for today i can, but i can't still uncompress .ace, and there are many people that cannot uncompress rar either... so please, it's something that it's no effort to you, you don't mind using rar or zip, but using the latter you make a lot of people's life easier... thank you :-)