I have an icon that looks like it was shrunk from a larger image. How can I easily clean up the text to make it look sharper?
Since you tags are Photoshop / GIMP I'm assuming you are working with raster images. The easiest way to fix this is to try and get your hands on a vector original of the logo and scale the vector artwork. The fuzziness you're seeing is probably due to antialiasing created when the raster image was scaled, and scaled, and scaled...
You could try using "Unsharp Mask" (Filter ->Sharpen -> Unsharp Mask) but that has its own set of issues, and you may have to go back by hand and fox some other areas. Depending on how complex your logo is it may actually be easier to fix the fuzzy edges with the brush tool.