Embedit lets you embed all sorts of file types directly on your site. It lets visitors see the document conveniently instead of downloading and viewing it in another application. It supports the typical Microsoft Office file types, along with Open Office. It also supports images and text files. The images don’t seem all that useful unless the image is much larger than what you can comfortable show on your site. The text files are handy though.
Here are two examples. The first is a Powerpoint presentation, the second is a JPEG.