this site might be interesting for you:
http://www.mm-log.com/lab-curves-gimp
Regards
Patrick
What exactly do you want to do in the L*a*b colour space?
Is it because of advanced sharpen issues?
Regards
Patrick
http://gimpfx-foundry.sourceforge.net/browse24/index_file.html
All the plugins are there, under Image->FX-Foundry->Color
Owen
I.e. a choice of one or more of either RGB, HSV, HSL, Hex, Lab, etc.,
etc., etc.