Create LOG files when creating multiple DATA files for tempdb? I've a question that I can't seem to find an answer to (and I can't test it out for a few weeks so I'm doing research now during my downtime). 

Should I be creating corresponding LOG files for every DATA file I create? 

eg. if I create tempdev3.mdf, should I also create templog3.ldf? 

Or do the LOG files get created automatically as and when needed by the SQL Server? 

I'm using MS SQL 2008 R2 EE but I think the answer equally applies to 2005 and 2012.
No, SQL Server only writes to 1 LOG file at a time. So it doesn't help to create multiple log files for better IO performance. It will use the first file and only when that one is full and no VLFs are cleared it will continue in the second file, etc. etc.

You might want to create a second log file if for example you run into an emergency situation where you run out of disk space on disk X and you want SQL server to continue logging in a second file on disk Y.