The most common types of interest are from bank accounts, mutual funds or bonds. That income will be reported in the top section, Part I, of Schedule B.
Part II is where you should see any dividend distributions you received from your stock or mutual fund holdings. If your total dividends are less than $400, you can just plop that number on line 9 of your 1040. If not, the detail will end up here.
Note that some distributions are long-term capital gain distributions, paid out by mutual funds and real estate investment trusts. (These numbers are reported in box 2a of Form 1099-DIV, which you should've received in the mail by now if you had any.) Since these distributions are subject to the long-term capital gains tax, they should first be reported on Schedule D, which we'll get to in a minute. But if you did not sell any stocks, bonds or mutual funds in 2000, you may not need to file Schedule D at all.
To avoid having to file Schedule D just for these distributions, make sure the box on line 13 of your 1040 is checked. This alerts the IRS not to look for those capital gain distributions on a Schedule D. But note that these distributions still have to be reported on Schedule B.
If you received fractional shares as a result of the bazillion splits and mergers this year, those shares will be reported on Schedule B as well.