How to use tar command in Windows XP?

Hello,

I would like to use tar command in Windows XP SP2 to extract the file name: OpenbravoERP-2.50XX.tar.bz2.

I try to follow the structure that I must use the tar command. I tried to use tar command on Command Prompt of Windows XP, but that doesn't work. I also tried to download GnuWin32 and installed, but it also doesn't work.

Please help me, How to do solve that?

Thanks,

Susan