You might want to try this great beta unzipping program: IZArc. It does .rar's and many/most others for free. (I forgot who suggested this, it may have been blazingwolf or buzzard. Props to him/her and sorry if I forgot who told me about this program.)
I'd recommend downloading it from one of the mirror sites listed, though, since the main page loads really slowly.
http://www.izsoft.dir.bg/izarc.htm
Mirror:
http://www.securitywonks.net/project...ad.php?file=12