1. http://www.e-crisp.org/E-CRISP/- currently the best online solution (Recommended).
2.http://crispr.mit.edu/ - MIT's online CRISPR tool is a little slow, but pretty decent if they support your genome of interest.
3. http://crispr.u-psud.fr/- simple but effective, supports analysis of any sequence for target-sites.
4. http://zifit.partners.org/ZiFiT/ - another simple but effective solution.
5. http://www.rgenome.net/cas-offinder/- select genomes only, but allows for alternative Cas9 species.
6. http://tools.flycrispr.molbio.wisc.edu/targetFinder/- a simple drosophila focused tool.
offline software
7. http://www.biootools.com/col.jsp?id=103 (sgRNAcas9) - a comprehensive command line tool (Recommended ).
8. http://arep.med.harvard.edu/CasFinder/ (CasFinder) - a good alternative to sgRNAcas9 if you are having trouble with that.
9. https://code.google.com/p/ssfinder/ (SSFinder) - a simple but effective tool, it will likely be slow for large genomes.