This converts not only document formats, but also image formats like .jpg, music formats like .mp3 and video formats like .rm. A complete list of all formats is given here.
Currently on the free Zamzar service you can upload a maximum of 100 MB of data split between up to 5 different files. If you signup for an account with Zamzar though you can upload files up to 1 GB in size. The pricing is like this:
Price File Size Concurrent Conversions Online Storage
Free 100 MB 5 Zero
$7 per month 200 MB 7 5 GB
$16 per month 400 MB 10 20 GB
$49 per month 1GB 15 100 GB
The name "Zamzar" is based on a character from the German author Franz Kafka's book "The Metamorphosis". In the novel Kafka describes the extraordinary story of a young man who is transformed whilst sleeping into a gigantic insect. The man's name - Gregor Samsa - was used as the basis for the company name because of its' powerful association with change & transformation.