The conversion from a traditional IRA to a Roth IRA depends on the nature of the dollars you used to fund the traditional IRA.
If you used pre-tax dollars to fund the traditional IRA, you cannot avoid paying ordinary income taxes on that amount. The amount you convert will be considered taxable income in the year of conversion. You can avoid the 10% early withdrawal penalty if those funds remain in the Roth account for five years and until you are past 59 ½ years of age.
If you made nondeductible contributions to the traditional IRA (i.e. paid from out of pocket money rather than being withheld from your paycheck) you may not have to pay taxes on the conversion. However, any earnings on the contributions at the time of conversion will be treated as taxable income.