Since: Dec 30, 2002
First off, do you need a pre-amp? Does your Recorder not have XLR inputs and Phantom Power? (+48v) (The name and model of the mixer would be handy).
If you do want / need a preamp then there are plenty on the market. I would personally reccomend a Joe Meek MQ3. This unit comprises of a single channel (XLR input with Phantom Powering), it features two outputs allowing you to monitor with effects (great for vocalists who often prefer lots of reverb in their headphone mix) along with the classic Joe Meek Compressor and a transparent 3 Band EQ. I've got one myself and I think they're excellent - worth every penny.
If you are looking for something a bit cheaper and / or need to record two microphones at the same time (and can't afford two MQ3's ;) then the M-Audio 'AudioBuddy' looks pretty sweet - that's got 2XLR's (with phantom powering) and has 2 seperate outputs (so you don't have to submix them onto one channel on your Recorder) It's currently only $80 on Musician's Friend, bargin!
Finally, if you are looking to do some serious mic'ing (eg: A Drum kit or Vocal Group) then you may consider the very nicley priced SM PR8. This unit offers 8 XLR inputs (all with phantom powering) and 8 balanced outputs.
Hope these were roughly what you were looking for - good luck!