MP3, AIF, M4A, AAC to OGG or CAF

Is there a way to convert at least one of any common music format to a .ogg or .caf file FOR FREE? Answers to the caff OR the ogg questions are greatly appreciated. I tried afconvert in Terminal, but I can't get it to convert it. I also tried searching for downloads. Nothing worked. I was all either Windows or stuff I had to buy.

I have a Windows, but I don't want to deal with it. I seriously have to burn rewritable DVDs to get stuff onto it; it's so old that it doesn't have a USB port, an iLink port, or a working network connection. It can't burn anything, so I don't even know yet how I'll get stuff off of it...