I have a gang of audio files that are in FLAC format that I would like to convert to MP3s. How would I go about converting them? I would like to retain the metadata if at all possible.

Use foobar2000.

Make sure you grab the Lame codec from Rarewares too.

Take your pick Lame 3.98b5 or Lame 3.97.

http://rarewares.org/

I've never used foobar to convert files before.... will this delete the FLACs that I convert? Because I want to retain the FLAC files that I am converting to .mp3s.

No.

Easy use Foobar convert tool, this is very good as it can keep any metadata from one file and tag it to the converted file accordingly, it will also add album art if it is in said file. Download Lame 3.97 from many places on the web (google is your friend) and place that in foobar2000 directory.

You can also tell foobar to rescan the new MP3s and add replaygain info once they've been converted too