I second the EAC with LAME MP3 encoder. I have not encoded anything to FLAC so could not make any recommendations.
However, if you want to convert FLAC to MP3 I would recommend using Foobar2000 with the LAME encoder (whichever is the most current stable release) to convert them. It's easy and FREE!

-james

"What can be asserted without evidence can also be dismissed without evidence." C Hitchens