Buleku / The best online dictionary resource for Manchu, featuring Manchu-English, Manchu-Chinese, Manchu-French, and Manchu-Manchu definitions for almost any Manchu word you might encounter.
Manc.hu / Has a variety of resources for reading Manchu texts. Perhaps its most useful feature is that it is almost certainly the largest searchable Manchu corpus available online.
Center for Manchu Studies / Research Institute for Korean Studies, Korea University, Seoul. (in Korean)
Research Materials for the Manchu Buddhist Canon / Dharma Drum Buddhist College 法鼓佛教學院, Taiwan. (in English and Chinese)
中華民國滿族協會 / Taipei, Taiwan
满族文化网 / China
Manchu Studies at National Chung Cheng University / 中正大學滿洲研究 National Chung Cheng University, Taiwan (in Chinese)
Fe doro: Manchu Archery / Peter Dekker, The Netherlands
Northeast China Non-Han Name Lexicon / Developed by Loretta Kim and her team at the University of Hong Kong. This is a great way to cross-reference Manchu and Chinese versions of names that you encounter in Qing official documents.
Qing archival documents at the National Palace Museum (Taiwan) website / Includes about 20,000 Manchu documents from the Qing archives