I just e-filed my 2010 taxes and have received a direct deposit of my refund already. I just realized I'd like to make a contribution to my Roth IRA (and my wife's) for 2010. How can I do this? Do I need to file an amended return?
No, you do not need to file an amended return, because Roth contributions are after tax contributions and are not reported on your return (UNLESS you over-contribute in which case you may have to pay a penalty on your return).
Make the contribution now before April 15 and you don't need to worry about it. Just make sure you are within the required contribution limits.