I need to convert mp3 files to 8KHz PCM-code 64Kbps bitrate wav file. Is this possible with lame or mpg123, or any other programmes?
I'd recommend Audacity. It's a free audio editing program that runs on Windows/Mac/Linux.
From poking around in the formats that you can export, if you save as type Other uncompressed files and select Options, you have the ability to select a WAV file Unsigned 8 bit PCM encoding which I believe is what you were looking for.