color:
http://www.webteknique.com/tutorials..._one/intro.asp
http://www.pixy.cz/apps/barvy/index-en.html
http://www.colorschemer.com/online.html
depends on what fileformat you have the logo in, if you can get a hold of the vector file it is the best, like .ai (adobe illustrator) .cdr (CorelDraw) .fhxx (freehand) .eps, if you cant and only have the .gif it will take some work