I'm using Profiler 2012, talking to 2008, 2008 R2, and 2012 databases. I had to use a slightly different workflow than in the accepted answer.
When I try to follow that workflow, to migrate a template from 2008 to 2012, the Select template name dropdown depopulates, and clicking Save or Save As prompts me to choose a template to save.
Instead, copy your template from the 2012 profiler, 2008 templates folder (should be
%APPDATA%\Microsoft\SQL Profiler\11.0\Templates\Microsoft SQL Server\100) to the 2012 profiler, 2012 templates folder (should be
%APPDATA%\Microsoft\SQL Profiler\11.0\Templates\Microsoft SQL Server\110)
Now, go to
File > New Trace... and choose the copied template to perform a trace on a 2012 server. Verify the trace is running and capturing what you want.
At this point, you're pretty good - you can use the copied template to start traces. But if you want to make modifications on it, when you go to
File > Templates > Edit Template... and choose Events Selection you get a prompt indicating the trace is in the wrong format:
To save it in the new format: start the trace running using
File > New Trace... as mentioned above, then with the trace running do
File > Save As > Trace Template... and choose a new name. You can now delete the originally copied template, and use the newly saved template in its place.