Type: Online self-study program
Cost: Free
Audience: Beginner to advanced
Website: http://indonesianway.com/
Update 21/2/2016 - This has changed completely, and looks to be a very promising resource. They have not finished, but have posted timelines and funding requirements. The Online Edition is free, but the Textbook Edition is for members only... with no visible way to become a member! Like I said, work in progress.
This is an online textbook with 113 lessons across 8 modules, covering several aspects of daily life in Indonesia. Many separate exercises, in addition to those embedded in the text, help test your knowledge.
The lessons are well-organised and have several useful features that a normal textbook couldn't - the most obvious being sound recordings embedded into the lesson. Another really useful feature is the audio transcriptions, which you have to click a button to show. When the temptation to read along is removed, I find it easier to concentrate on the audio. You can display a word list for the lesson, as well as flashcards to help drill the information.
The audio is clear and spoken at a speed you might actually hear in Indonesia - hard at first but better to get used to it now than expect everyone to speak at a snail's pace to you. When the audio is for one word only, they have a male and a female say it which is good, because in any language two people can pronounce the same word a little differently and still be correct.
There are little self-tests you can do along the way, with an input format from the 90's but it gets the job done. There is no 'fudge factor'. For example, if the answer is "United States", you cannot put "United States of America", "USA" or "America". Similarly, if there is a spelling error at their end, tough luck. One example is "Phillipines" [sic]. In some of the exercises it's hard to know which answer they want, for example if 3 of the pictures look like they could be a school, which one is "sekolah" and what the heck are the other three? But they do give you assistance after the first try and since there is no scorekeeping, it doesn't really matter: the important part is that you're learning.
Some of the lessons have some strange things to learn, for example in Lesson 2 you go through a whole exercise containing versions of "I'm from Russia." "Huh? I thought you were from Germany." "Nope I'm from Russia. There is quite a bit of variety though, and several ways to say the same thing. You might not remember them all to use yourself, but if you see or hear them later it will make sense. They also add little bits that people would actually say, so in response to "Dari mana", rather than saying "from my house", you might say "only from my house". It adds words that people are likely to use in everyday conversation, I think if you can pick up some of these words it will make you blend in a lot better in Indonesia.
One final note - if you get stuck on the first page of the module like I did, take note of the little orange arrows at the top right hand corner of the screen. They're your navigation buttons!
The Indonesian Way is maintained by University of Hawai'i at Manoa. It is used for their online-delivered Indonesian program, which I will not review as it costs around USD $500, but which sounds fantastic. The courses use a number of other resources as students progress, but since I'm at Beginner stage still, we'll take them one step at a time!