If you received $10 or more of interest from a bank or broker, you would have received a 1099-INT no later than the end of February. A brokerage house will typically send a single tax information packet which has 1099-INT, 1099-DIV, 1099-OID, and/or 1099-B listed together.
Even if you didn't receive a 1099-INT, you can always look at your bank statements to find how much was paid during the year. Banks often provide a year-to-date (YTD) figure on the December statement. If you did receive 50 cents of more of interest, you can enter it manually, just giving the bank name and the amount of interest in Box 1. It almost never changes your tax, but is a bit of insurance that should something get screwed up in the future, the IRS will see that you are an honest taxpayer and not a tax cheat.