This site is actually really easy to get started with and willing to let you study without bothering you.
Regarding the approach (type in a translation for the requested term), I am a bit sceptical. It seems to require that there is one unique translation for each term. Maybe multiple choice would be better? This would also solve the irritating keymap for foreign language problem (http://smart.fm solves this nicely with a custom input mechanism in flash).
I've tried Rosetta, smart.fm, others that score you based on your input, but by far the simplest and best method I've found is using Anki, which just asks you 'did you remember it?' and it's up to you to answer truthfully.
Regarding the approach (type in a translation for the requested term), I am a bit sceptical. It seems to require that there is one unique translation for each term. Maybe multiple choice would be better? This would also solve the irritating keymap for foreign language problem (http://smart.fm solves this nicely with a custom input mechanism in flash).