$4,000 for tax years 2006-2007.
$5,000 for tax year 2008.
After 2008: limit adjusted for inflation in $500 increments.
Catch-up contributions for workers age 50 and older (as of year's end): $1,000 extra in 2006 and thereafter.

$4,000 for tax years 2006-2007.
$5,000 for tax year 2008.
After 2008: limit adjusted for inflation in $500 increments.
Catch-up contributions for workers age 50 and older (as of year's end): $1,000 extra in 2006 and thereafter.

Yes, depending on participation in retirement plans and modified adjusted gross income (MAGI).
For tax year 2006, full deductibility of contributions for active participants in a retirement plan whose MAGI is $75,000 or less (joint) and $50,000 or less (single).
For tax year 2006, partial deductibility for up to $85,000 MAGI (joint) and $60,000 (single).

No.

Ordinary income tax on withdrawals of earnings and deductible contributions.
No federal taxes on withdrawals of nondeductible contributions. State taxes may apply.

Tax-free earnings if you hold the account for at least five years and are 59½ or older upon withdrawal, or if your withdrawal qualifies as an exception described below State taxes may apply.