I’m writing this post because the rest of the interwebs seems to be hopelessly out of date. Hopefully some search engine will find my site and lead people here.
Anyway, the location of the log files for Empathy in Ubuntu 10x-11.x is: ./.local/share/TpLogger/logs/
This is because while the default bundled IM client is Empathy, it is used as a part of Telepathy (hence the “TpLogger” part). It is annoying as anything to figure this out especially since (as of this date), the official FAQ does not come up as part of the top 5 search results on Google.