I recently met a lead whose business card read “Lead Phoenix Developer.” I asked what that meant, and he explained that he was a technical lead for an project code-named Phoenix. His business card could have read “Lead Developer” or “Technical Lead” and made much more sense.
This almost happened to me today. I’m the conference chair (the program manager for the whole conference) for Agile 2009 (in Chicago, August 2009). Internally, I think that position is called “program director”–but I’m not selecting any part of the actual conference. The program piece is that the position is like a program manager position. I asked to be called the conference chair instead. That’s what I’ll be calling myself!
If you have internal names for jobs, that’s fine. Keep the internal and external names separate.