We anticipate making some money from stock market this year but won't know how much until the end of the year. Just calculating the salaries, we won't exceed the $150K limit but if we do make as much as we did from stock market in 1999, we will have an AGI between $150K and $160K. Does that mean we shouldn't contribute until we need what our real AGI is until the end of the year? Or can I contribute the $2K now and withdraw the extra contribution if our AGI does exceed $150K by the end of the year? Will there be penalty doing so? Please advise. Thanks.

You can either withdraw any excess, or recharacterize it so that it will be considered a contribution to a traditional IRA.