This tool is good !! You just email the content be it a document that needs to be made into pdf , or a 3gp file into another video format ( AVI , Mpeg ) or vice versa and its done and ready to download , and yes it converts into heaps of formats.
Converts Audio ,Video and document formats online
I came across this “zamsar online conversion tool” long ago and then lost the link in my email and did not bookmark it , did a few video conversions for my 3gp files . worked beautifully. They email you back the converted link when its done for download . I dont need it anymore most new phones now have the AVI of 4mpeg format , but its still handy for converting other stuff
ZAMZAR is a Magic Free online converter
Zamzar, a popular tool for converting files online, has added a new option that lets you convert files by email itself. You can forward your email attachments directly to Zamzar, without downloading them to the desktop, and they’ll be converted in no time.
Here is a full list of what it converts online . Im sure you will add this to your book marks , and do add my blog and give it a like or tweet or whateva 
Go to zamzar here
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In love this tip…ius now on my fav list