Michel Thomas is an excellent starting point. I would reccommend that you do the beginner's and advanced courses as quickly as possible. You will still not be brilliant but you will have a good base that you can build on. I would then reccommend that you get an Assimil course which is basically just 4CDs with dialogues on them and a seperate book with a transcription in both your target language and English, some notes on grammar points and some very basic exercises. Very simple but I find it to be one of the most effective courses out there and it is comparitvely cheap (about £50).
It should take about 6 months to complete both of those by which point you can consider yourself to be at an intermediate level and can probably start using native material a lot more (i.e. TV shows in your target language).
I would not recommend Rosetta Stone. It is hideously expensive for what it is and the last time I used it, it just seemed to be teaching single words and very short phrases with absolutly no explanations given. Also, as said before, it doesn't even show he English translation of what you are learning and just gives a picture which might be ambiguous. Pimsleur is good for developing a good accent in your language but it ridiculously slow paced and after 3 months, you will still have very little understanding of your chosen language and again, it is stupidly overpriced.
