@69VanNuys - Start with the first year that there was a non deductible contribution and fill out a 8606 form for THAT year with the non-deductible contribution on line 1. The amount on line 14 will carry to line 2 of the next years 8606 and will be added to that years line 1 contribution. Repeat for each year that there was a non-deductible contribution until current.
You can download past years 8606 forms (and instructions) from the IRS here:
Mail the 8606 forms to the IRS: