GIMP is good for image manipulation. If you design a logo maybe you want do some vector graphics first - for this purpose Inkscape or OpenOffice/LibreOffice Draw are common open source programs. Later you can make graphicts with effect with this logos in GIMP.
Software are not good in logo creation because it is all about creativity and uniqueness so don't create your logo with the help of software. You need to hire professional logo designers because only professionals can create a unique and best logo.
Software can't provide your creative and unique logos, if you want to get best business logo design you need to hire professional logo designing company because only professional designers can provide you best logos.
I did not mean vector graphics software can replace you a logo designer. Just that vector graphics software is more suitable for making logos than pixel based ones. If you want a good logo and are very gifted you can have a try - but I recommend then to show the logo to some critical minds before publishing. Best way for serious stuff is to hire a designer - you can find a good quality/price ratio surely. But, well, its a logo - something people will identify with you so better take a little more money and time for this. And also check Google for things like "epic logo fail" etc. to see how not to do a logo