The story of Jaya and Vijaya told beautifully and concisely by a member of Yahoo Answers:
Jaya and Vijaya are the two gatekeepers, dwarapalakas of the abode of Vishnu, known as Vaikuntha Loga. According to the Bhagavata Purana, the Four Kumaras, Sanaka, Sanandana, Sanatana, and Sanatkumara who are the manasaputras of Brahma (sons born from the mind or thought power of Brahma), visit Vaikuntha, the abode of Vishnu, to see him. Due to the strength of their tapas, the four Kumaras appear to be mere children, though they are of great age. Jaya and Vijaya, the gate keepers of the Vaikuntha interrupt the Kumaras at the gate, thinking them to be children. They also tell the Kumaras that Sri Vishnu is resting and that they cannot see him now. The enraged Kumaras replied Jaya and Vijaya that Vishnu is available for his devotees any time, and cursed both the Dwara Palakas, the gate keepers Jaya and Vijaya, that they would have to give up their divinity, be born as mortals on Earth and live like normal human beings.