Zamzar is a web application that allows you to convert files without downloading a software tool.
All you need to do is type in a URL or upload one or more files (of the same format). Zamzar then converts the files into another format. So for example, want to listen to the audio from a Flash file in MP3 format? Simply upload the flash file and convert to MP3, wait a while and youçll receive an e-mail when the converted file is ready for downloading.
The basic version of Zamzar is free to use although you can choose to pay a monthly subscription which extends functionality such as as online file management, quicker queuing and conversion times etc. Conversions are generally excellent although there does seem to be the odd error or reformatting issues occasionally. However, the main concern is that anything you upload inevitably involves compromising your privacy and it's not clear if Zamzar can claim intellectual property rights over your material.
Overall though, Zamzar is a very useful way to perform file conversions without having to download an application.