The epstopdf script transforms an Encapsulated PostScript (EPS) file to a PDF file with a PDF page size exactly corresponding to the EPS BoundingBox (or, optionally, the HiResBoundingBox or ExactBoundingBox). It is written in Perl and (by default) uses Ghostscript.
Primary distribution and downloads are through CTAN. The TeX Live and MiKTeX distributions include it.
The epstopdf documentation is available here. It is also included in the distribution.
The Subversion source repository for Epstopdf is kept as part of TeX Live, for the developers' convenience. The source repository includes a few tests that are not distributed.
Mailing list for bugs and discussion: tex-k@tug.org. When reporting bugs, please include an input file and all specified command line options, so the problem can be reproduced.