If you want to read about it, check out the Fool School and Retirement planning page. There are also numerous books on retirement planning. Most include sections on IRA's and Roth IRA.

When in doubt, go with the Roth (if you qualify). It works best for those in lower tax brackets who likely will be in higher tax brackets at retirement. But the real issue for retirement is 401K and what to do with Rollovers. Its hard to accumulate much in an IRA with $2K/yr contributions. 401Ks (and related other plans) allow $10K and up. That's where the money is.