I'm running IGV 2.0.10 on Mac OS X Snow Leopard, located at:
/Applications/IGV 2.0.app/
It took a little guess work, but I found the igv.log lives here under
my home directory:
~/.igv/igv.log
Could this be added to the FAQ (for all platforms) please?
http://www.broadinstitute.org/igv/FAQ
Thanks,
Peter