This is an online tool that will allow you to convert your files without ever having a need to download any file conversion software.
One such useful website is [ZAMZAR], which does online file conversions without needing you to download any software. All you have to do is open the website, select the file to convert, then select the file format to convert to and enter your email address to receive the converted file. There are plenty of file formats supported for conversion [upto 100MB in size].
Some of the most popular file formats to which files can be converted to are:
Image Format: bmp, gif, jpeg, png and tiff
Document formats: csv, doc, html, pdf, ppt, rtf, ppt, txt and xls
Music Formats: aac, ac3, mp3, wav, wma and ogg
Video Formats: ipod, avi, mpg, mov and mp4