Hi Chemist2, the only part that is taxable when you convert to Roth is anything over your basis. If you contribute 6K (non-deductible) to a traditional IRA and immediately move it to a Roth, there would be no tax on that (assuming you earned no interest on that 6K before you moved it.
Again, this is in an example where my son would open a traditional IRA (doesn't have one now) and dumped 6K into it and immediately transferred to Roth.