BahasaKita is an online Indonesian language resource which offers a variety of useful information for learners and teachers alike.
This website covers formal grammar such as word order, sentence structure, verbs, pronouns, prefixes, suffixes, conflixes, reduplication, prepositions, temporal markers, negation, classifiers and particles. In addition, colloquial Bahasa Indonesia for many of these same topics is covered for those who will be traveling and interacting with people speaking non-standard Indonesian.
Furthermore, useful information about pronunciation of vowels and consonants, a glossary, a quick guide and slang resources are also provided.
Beyond the Indonesian language itself, BahasaKita offers general information about Indonesia's history, culture, landmarks, nature and cooking. These will be particularly useful for travelers and folks interested in getting acquainted with the country before or during a visit.
All in all, this is a good resource for diving into Indonesian as a beginner, getting an overview of grammar and colloqualisms, picking up some slang and garnishing useful cultural and linguistic insights.