If you are really on a shoestring (i.e. you cannot afford a graphic designer), then I would really recommend Inkscape - which is to Illustrator as Gimp is to Photoshop. It's a bit foreign if you've never done vector graphics before, but if you're working on logos it really is the way to go. For colors & palletes, go over to colourlovers.com - that's a good place to start anyway. If you are only after the odd pic or two, any of the stock photo sites is good and relatively inexpensive. Also, there are a ton of sites such as deviantart.com where you can find free graphics and fonts, etc. or at the very least you can find some really talented artists that might be able to get it done for you.