One of the more frustrating things about collaborating with colleagues and customers on projects is that they often use different editing software than you do. This, in turn, can cause the documents, images, and presentations you're dealing with to get garbled in translation. Just because your client refuses to pony up for Microsoft Office, though, doesn't mean that you're doomed to spend time erasing the weird little symbols that show up in all the forms he sends you. There are several free sites and software programs that tackle this exact problem.
As the guys at the Lifehacker blog noted late last year, there are two websites that convert sound, text, image, and video files up to 100MB to other formats quickly and without too much trouble. (Think .jpg to .gif for an image file or .pdf to .rtf for a text file.) Zamzar has the cleanest and easiest look, and saves you the trouble of inputting the type of file you are converting from. Plus, the resulting file is downloaded from a url you can simply send to the person you're working with. If you need more formats to choose from (but care less about the aesthetics of the site), check out media-convert, which works just as well for me, plus it has few more bells and whistles (like quickly turning a whole webpage into an image file).