I could wrap it all in a ball and sell you it , or you can just make it yourself inhouse.
an online mobile video converter
First give them a collection of your own content preconverted files in popular mobile formats 3gp, mp4 etc
Then give them an online file converter for them to convert their own videos to mobile formats.
There are many free online video converters but they are usually cumbersome or slow because theres shitloads of people who don't want to pay so they get overloaded as soon as they become popular.
A cross-sale the surfer
might actually want and very cheap to setup.
cheers , smokey.