I already did my googling and found the Java applet and one or two Flash thingies.
I wanted to write a webservice where people can fetch and create vocabulary files for foreign languages - which are endlessly more efficient if you've got something _spoken_ in addition to just seeing the word.
And as things tend to work very much better if the access to participation is easy, I though of a nice website.. like "ok, let's speak some new spanish words, let's see, what's missing..." and people would essentially just have to read out loud in their headset.
Something like this.
(And bundle it nicely tagged per subject for easier learning and write a nice Python tool to use it on Nokia S60 based cell phones while sitting in the bus/metro/hanging around somewhere and waiting and so on...)