TwitDoc is free to use tool which allows you to upload any file on your computer to twitter.com, provided you have a valid working twitter account. It is an adobe air application which simply allows you to upload files on your computer.
You can upload any of the supported format file with application just by dragging and dropping the file on the application.
Supported media / file types for upload with TwitDoc are
Documents Files up to 15 MB. Word (doc, docx), PowerPoint (ppt, pptx, pps), Excel (xls, xlsx), PDF, PS, Open Office (odt, odp, sxw, sxl), and text (txt, rtf).
Graphics / Photos: Files up to 10 MB. File extensions are jpg, png, and gif.
Videos: Files up to 25 MB. File extensions are avi, mov, qt, mpg, mpeg, mp4, m4v, wmv, and flv. These are supported on an experimental basis. Please be aware that there may be substantial processing times before an uploaded video becomes visible.