There are a few places to go.
www.hydrogenaudio.org is the best audiophile forum about. Some things seem a little complicated but look for the reccommended settings and lame compiles threads.
Also some a good walk through
here
at the end of the day if you are looking to get the best quality sound files then you should probably be looking at other file formats. MP3 is a lossy format which means that no matter how good it is it is not an exact copy of the origional. It's not even the best lossy format out there but is the most cross compatible with hardware devices.
For true great sound files you need to us a lossless format like FLAC or APE (Monkeys Audio). Look around the sites above and you will find out about them.
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