Vyoma-Saṃskṛta-Pāṭhaśālā - the largest repository of structured Sanskrit e-learning content.
AVG-Sanskrit - A website to archive online Sanskrit classes given at the Arsha Vidya Gurukulam. An extraordinary collection of resources.
Ashtadhyayi site - When one looks at this site one wonders how a single person can do such amazing work. A thousand and one naman to Shri Neelesh Bodas for doing this for Sanskrit lovers. This site has Ashtadhyayi, Dhatu forms, and many brilliant tools with great search features.
Samskrita Vyakaranam - This site has wonderful notes on learning Sanskrit grammar following the style of Professor Pushpa Dikshit. The creator of this site, Swarup bhai, is an amazing and multifaceted dynamo. A thousand and one naman to him.
Girvanaprathistha - Shri Chitrapur Math - Material from a six month course. Excellent Quality.
Sanskrit World - There is little about Sanskrit that is not on this site. The inspiration behind this site is Dr Dhaval Patel, IAS. This site has tools that will amaze you.
संस्कृताभ्यासः - Sanskrit Abhyaasa - A great site with rich contents and plenty of exercises to test your understanding and learning.
Sanskrit Heritage site - It provides various services for the computational treatment of Sanskrit. This site was created by a French Sanskrit scholar and it was some 20 years ahead of the rest in providing computational tools for Sanskrit.
English to Sanskrit - An online dictionary to help with Spoken Sanskrit. It also has Sanskrit to English dictionaries working behind the scene.
Sanskrit Today - This site has dictionaries which includes कृदन्तरूपमाला and other dictionaries. This site also has great Sanskrit learning tools.
GoldenDict or Stardict Files Install Goldendict - Windows, Mac OSGoldendict supports many formats. This is a display program only and the user has to provide the dictionaries.
After installing Goldendict, please install dictionaries of choice.
Sanskrit - English Dictionaries - download the tar.gz files Sanskrit - English Dictionaries (some more) - download the tar.gz files Sanskrit - Sanskrit Dictionaries - download the tar.gz files Sanskrit - Vyakaran Dictionaries - download the tar.gz files Sanskrit - Kavya Dictionaries - download the tar.gz files
Download the tar.gz files that you want. There are many different dictionaries, please choose the ones you want to download. Even if you download all of them it's fine. Goldendict is very fast and it can deal with 10-15 dictionaries in no time. Please unzip, untar these files (use 7zip or any unzipping program) and keep them in a folder and point GoldenDict (Edit -> Dictionaries) to that folder.
For example, if you want to use apte.tar.gz, unzip and untar this file, create a folder `apte' (or any name of your choice), and then copy the files from apte.tar.gz (apte.dict, apte.idx, apte.info) into this `apte' directory. You can then add this folder, `apte', in GoldenDict via (Edit -> Dictionaries). Please note that instead of .dict, the files may also have an extension .dict.dz. There may be also a file with extension .syn. I think it will work as long as you have the .dict or .dict.dz file.
Ajit Krishnan notes on Aupasana - on iOS, use the “dictionary universal” application: on android devices, use the “colorDict” application: on windows, use the “goldendict” app: on mac osx, use the “goldendict” app.
Sanskrit Documents
Sanskrit Documents - A great contribution by Dr Nandakishore Abhayankar for the promotion of Sanskrit. Nandakishoreji was also some 25 years ahead of everyone. As the name suggests it has thousands of Sanskrit documents. Please check it out.
Aupasana - This site is a collection of various documents which may be of interest to āstikas. Many of them come from the "digital library of india" project. A few original publications are offered here as well.
Sanskrit Texts - This is a wiki source site with many Sanskrit texts.
Bhagavad Gita Online - There is a word for word translation and a recitation of every shloka. This is a good resource for learning Sanskrit through Gita.
Gita super site - The name has it all. This is a brilliant site created and maintained by IIT Kanpur. It was also at least 20 years ahead of the rest. It has various commentaries by authorities such as Ramanujacharya and Shankaracharya. It has Ramayan and other scriptures as a bonus.
Bhagavad Gita - Grammatical Analysis for Students of Sanskrit - by Medha Michika . Thi has resolution of sandhi, grammatical and etymological explanations of each word of श्रीमद्-भगवद्-गीता [śrīmad-bhagavad-gītā]
Adishila - आदिशिला - Rare books in unicode searchable form, e.g., Meghaduta and Raghuvamsham with Mallinath commentary, pure gold.