This is a very incomplete list and it will grow in the future...
It is not clear which one is the best. I have found some entries that are better translated in either one... and there are many more dictionaries available.
LEO - created at TU Munich, is a very good German-English dictionary with many entries, and dictionaries between German and other languages
BEOLINGUS - created at TU Chemnitz, very good German-English dictionary
These are explaining German words in German, but they are very comprehensive, explaining usage and Grammar etc.
Duden - the authority among German dictionaries, comparable to Merriam-Webster in the US, or Oxford Dictionaries in the UK
We are aiming at preparing interested students for some nationally recognized exams to have an impartial assessment of the school's quality and to offer students a tangible result of their work at the school. One example are the exams of the American Association of Teachers of German (AATG), which are widely known and accepted. These exams are offered in Levels 1 through 4. Each level corresponds to one year of instruction at the American high school level, or to two years of instruction at the Saturday school level. Saturday schools, such as ours, are considered to teach at approximately half the speed of an American high school. Here, we provide the AATG Level 1 Exam from 1992 for self-assessment. Students are encouraged to take the test in 65 minutes and give it to the school coordinator for grading.
Currently, we are exploring language learning software, which could help interested students to increase practice time during the week. One software we have currently available for testing is Tell Me More - German (company, online store). In reviews, this software seems to be the current leader of the pack, professional grade, and with versatility to adapt to beginners or advanced learners alike. However, we are in the exploratory stage and we would be curious to learn about other software, for example about the ubiquitous Rosetta Stone. If you have experience with this or any other package, we would love to learn what you think.