Apollo  is a sequence annotation tool and is available here. It was written and used as part of the BDGP annotation group for annotating the Drosophila genome.
- Lewis SE, Searle SM, Harris N, Gibson M, Lyer V, Richter J, Wiel C, Bayraktaroglir L, Birney E, Crosby MA, Kaminker JS, Matthews BB, Prochnik SE, Smithy CD, Tupy JL, Rubin GM, Misra S, Mungall CJ, and Clamp ME. Apollo: a sequence annotation editor. Genome Biol. 2002;3(12):RESEARCH0082.