The Hindu Endowment Board's website offers links to Hindu temples in Singapore, the Singapore Hindu - HEB's newsletter available online, festival dates and other hindu activities. The website of the Sri Thenduyathani Temple provides similar details such as images and links to local Hindu temples, festivals and the history of Chettiars in Singapore.
There are several online papers and analysis that provide a useful overview of Hinduism and its practices in Singapore. The Murugan Bhakti website has articles on Thaipusam and on Murugan temples in Singapore. Masakazu Tanaka has an online paper on Hinduism in Singapore.