The main difference is in the possible tax treatment. With a Roth IRA, the funds you are contributing have already been taxed (through your regular income tax), but your earnings are NOT taxed when you withdraw them in retirement. Funds you contribute to a Traditional IRA may be tax deductible, but you DO pay taxes on the earnings when they are withdrawn. There may be income restrictions and other differences, so always consult a tax professional to see what is possible for your specific situation.
With a Roth IRA, you can withdraw contributions at any time free of tax or penalty. Earnings are income tax free if you've held the account for 5+ years and you are 59 1/2 or older.
What is the maximum per year I can contribute to my IRA?
There are several factors that play into your specific contribution limit, and it can change from year to year. We recommend you consult a tax professional or the IRS website for the most current information.