Express powers are powers that the Constitution explicitly grants to the Federal government. Some of these powers are: Collecting Taxes, Regulate interstate commerce, coin money, set standards of weights and measures, declare war, and raise and maintain a navy and an army. So in other words these are the the things stated in the constitution that the government has the power to do.
Implied powers are all of the aspects that go in to supporting the express powers. The implied powers are what is considered necessary to carry out the express powers. Like the first example-the government couldn't raise an army if they weren't allowed to establish a draft. The implied powers are sort of like the writing between the lines in a contact.