Yahoo! Groups : lakhotaiyapi - This discussion group is helpful for learning to read and write Lakota. The site has a good number of knowledgeable members who can assist with specific questions. - http://groups.yahoo.com/group/lakhotaiyapi/
Lakota Language Consortium - A nonprofit organization working to revitalize the Lakota language. Site provides current Lakota language usage statistics as well as curriculum materials for elementary school age learners. - http://www.lakhota.org/
Lakota and Dakota Language Resources - Most comprehensive list of Lakota language-related resources and materials. - http://puffin.creighton.edu/lakota/index_language.html
Siouan Language Family Linguistic Listserv Archive - The best academic resource for Siouan language related issues, including news related to Proto-languages, borrowings, and other descriptive topics. - http://listserv.linguistlist.org/archives/siouan.html
Siouan Texts - This site has the largest collection of Lakota language texts on the internet. Great work by a committed linguist. - http://www.inext.cz/siouan/